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NAME

       proc - process information pseudo-file system

DESCRIPTION

       The  proc  file  system  is  a  pseudo-file  system which is used as an
       interface to kernel data structures.  It is commonly mounted at  /proc.
       Most  of  it  is read-only, but some files allow kernel variables to be
       changed.

       The following outline gives a quick tour through the /proc hierarchy.

       /proc/[pid]
              There is a numerical subdirectory for each running process;  the
              subdirectory is named by the process ID.  Each such subdirectory
              contains the following pseudo-files and directories.

       /proc/[pid]/auxv (since 2.6.0-test7)
              This contains the contents of the  ELF  interpreter  information
              passed  to the process at exec time.  The format is one unsigned
              long ID plus one unsigned long value for each entry.   The  last
              entry contains two zeros.

       /proc/[pid]/cmdline
              This holds the complete command line for the process, unless the
              process is a zombie.  In the latter case, there  is  nothing  in
              this  file:  that  is,  a  read  on  this  file  will  return  0
              characters.  The command-line arguments appear in this file as a
              set  of  strings  separated by null bytes ('\0'), with a further
              null byte after the last string.

       /proc/[pid]/coredump_filter (since kernel 2.6.23)
              See core(5).

       /proc/[pid]/cpuset (since kernel 2.6.12)
              See cpuset(7).

       /proc/[pid]/cwd
              This is a symbolic link to the current working directory of  the
              process.   To  find out the current working directory of process
              20, for instance, you can do this:

                  $ cd /proc/20/cwd; /bin/pwd

              Note that the pwd command is often a shell built-in,  and  might
              not work properly.  In bash(1), you may use pwd -P.

              In  a  multithreaded process, the contents of this symbolic link
              are not available if the  main  thread  has  already  terminated
              (typically by calling pthread_exit(3)).

       /proc/[pid]/environ
              This file contains the environment for the process.  The entries
              are separated by null bytes ('\0'), and there may be a null byte
              at  the  end.   Thus, to print out the environment of process 1,
              you would do:

                  $ (cat /proc/1/environ; echo) | tr '\000' '\n'

       /proc/[pid]/exe
              Under Linux  2.2  and  later,  this  file  is  a  symbolic  link
              containing  the  actual  pathname of the executed command.  This
              symbolic link can be dereferenced normally; attempting  to  open
              it  will open the executable.  You can even type /proc/[pid]/exe
              to run another copy of the same executable as is  being  run  by
              process [pid].  In a multithreaded process, the contents of this
              symbolic link are not available if the main thread  has  already
              terminated (typically by calling pthread_exit(3)).

              Under  Linux 2.0 and earlier /proc/[pid]/exe is a pointer to the
              binary which was executed, and appears as a  symbolic  link.   A
              readlink(2)  call  on this file under Linux 2.0 returns a string
              in the format:

                  [device]:inode

              For example, [0301]:1502 would be inode 1502 on device major  03
              (IDE,  MFM,  etc. drives) minor 01 (first partition on the first
              drive).

              find(1) with the -inum option can be used to locate the file.

       /proc/[pid]/fd
              This is a subdirectory containing one entry for each file  which
              the process has open, named by its file descriptor, and which is
              a symbolic link to the actual file.  Thus, 0 is standard  input,
              1 standard output, 2 standard error, etc.

              In  a  multithreaded process, the contents of this directory are
              not  available  if  the  main  thread  has  already   terminated
              (typically by calling pthread_exit(3)).

              Programs  that  will take a filename as a command-line argument,
              but will not take input from standard input if  no  argument  is
              supplied,  or  that  write  to  a  file  named as a command-line
              argument, but will not send their output to standard  output  if
              no  argument  is  supplied,  can  nevertheless  be  made  to use
              standard  input  or  standard  out  using  /proc/[pid]/fd.   For
              example,  assuming that -i is the flag designating an input file
              and -o is the flag designating an output file:

                  $ foobar -i /proc/self/fd/0 -o /proc/self/fd/1 ...

              and you have a working filter.

              /proc/self/fd/N is approximately the same as /dev/fd/N  in  some
              UNIX   and   UNIX-like  systems.   Most  Linux  MAKEDEV  scripts
              symbolically link /dev/fd to /proc/self/fd, in fact.

              Most systems provide symbolic links /dev/stdin, /dev/stdout, and
              /dev/stderr, which respectively link to the files 0, 1, and 2 in
              /proc/self/fd.  Thus the example command above could be  written
              as:

                  $ foobar -i /dev/stdin -o /dev/stdout ...

       /proc/[pid]/fdinfo/ (since kernel 2.6.22)
              This  is a subdirectory containing one entry for each file which
              the process  has  open,  named  by  its  file  descriptor.   The
              contents  of  each  file can be read to obtain information about
              the corresponding file descriptor, for example:

                  $ cat /proc/12015/fdinfo/4
                  pos:    1000
                  flags:  01002002

              The pos field is a  decimal  number  showing  the  current  file
              offset.   The  flags  field is an octal number that displays the
              file access mode and file status flags (see open(2)).

              The files in this directory are readable only by  the  owner  of
              the process.

       /proc/[pid]/limits (since kernel 2.6.24)
              This  file  displays  the  soft  limit, hard limit, and units of
              measurement for each  of  the  process's  resource  limits  (see
              getrlimit(2)).   The  file is protected to only allow reading by
              the real UID of the process.

       /proc/[pid]/maps
              A file containing the currently mapped memory regions and  their
              access permissions.

              The format is:

              address           perms offset  dev   inode   pathname
              08048000-08056000 r-xp 00000000 03:0c 64593   /usr/sbin/gpm
              08056000-08058000 rw-p 0000d000 03:0c 64593   /usr/sbin/gpm
              08058000-0805b000 rwxp 00000000 00:00 0
              40000000-40013000 r-xp 00000000 03:0c 4165    /lib/ld-2.2.4.so
              40013000-40015000 rw-p 00012000 03:0c 4165    /lib/ld-2.2.4.so
              4001f000-40135000 r-xp 00000000 03:0c 45494   /lib/libc-2.2.4.so
              40135000-4013e000 rw-p 00115000 03:0c 45494   /lib/libc-2.2.4.so
              4013e000-40142000 rw-p 00000000 00:00 0
              bffff000-c0000000 rwxp 00000000 00:00 0

              where  "address"  is  the  address  space in the process that it
              occupies, "perms" is a set of permissions:

                   r = read
                   w = write
                   x = execute
                   s = shared
                   p = private (copy on write)

              "offset" is the offset into  the  file/whatever,  "dev"  is  the
              device  (major:minor),  and "inode" is the inode on that device.
              0 indicates that no inode is associated with the memory  region,
              as the case would be with BSS (uninitialized data).

              Under Linux 2.0 there is no field giving pathname.

       /proc/[pid]/mem
              This  file can be used to access the pages of a process's memory
              through open(2), read(2), and lseek(2).

       /proc/[pid]/mountinfo (since Linux 2.6.26)
              This file contains information about mount points.  It  contains
              lines of the form:

              36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
              (1)(2)(3)   (4)   (5)      (6)      (7)   (8) (9)   (10)         (11)

              The  numbers  in  parentheses  are  labels  for the descriptions
              below:

              (1)  mount ID: unique identifier of the  mount  (may  be  reused
                   after umount(2)).

              (2)  parent  ID:  ID  of parent mount (or of self for the top of
                   the mount tree).

              (3)  major:minor: value of st_dev for files on file system  (see
                   stat(2)).

              (4)  root: root of the mount within the file system.

              (5)  mount point: mount point relative to the process's root.

              (6)  mount options: per-mount options.

              (7)  optional   fields:   zero   or  more  fields  of  the  form
                   "tag[:value]".

              (8)  separator: marks the end of the optional fields.

              (9)  file  system  type:  name  of  file  system  in  the   form
                   "type[.subtype]".

              (10) mount source: file system-specific information or "none".

              (11) super options: per-super block options.

              Parsers   should   ignore   all  unrecognized  optional  fields.
              Currently the possible optional fields are:

                   shared:X          mount is shared in peer group X

                   master:X          mount is slave to peer group X

                   propagate_from:X  mount is slave and  receives  propagation
                                     from peer group X (*)

                   unbindable        mount is unbindable

              (*)  X  is  the  closest dominant peer group under the process's
              root.  If X is the immediate master of the mount, or if there is
              no  dominant  peer  group  under  the  same  root, then only the
              "master:X" field  is  present  and  not  the  "propagate_from:X"
              field.

              For    more    information    on    mount    propagation    see:
              Documentation/filesystems/sharedsubtree.txt in the kernel source
              tree.

       /proc/[pid]/mounts (since Linux 2.4.19)
              This  is a list of all the file systems currently mounted in the
              process's  mount  namespace.   The  format  of  this   file   is
              documented  in fstab(5).  Since kernel version 2.6.15, this file
              is pollable: after opening the file for  reading,  a  change  in
              this  file  (i.e.,  a  file  system  mount  or  unmount)  causes
              select(2) to mark the file descriptor as readable,  and  poll(2)
              and epoll_wait(2) mark the file as having an error condition.

       /proc/[pid]/mountstats (since Linux 2.6.17)
              This   file   exports   information  (statistics,  configuration
              information) about the mount points in the process's name space.
              Lines in this file have the form:

              device /dev/sda7 mounted on /home with fstype ext3 [statistics]
              (       1      )            ( 2 )             (3 ) (4)

              The fields in each line are:

              (1)  The  name  of the mounted device (or "nodevice" if there is
                   no corresponding device).

              (2)  The mount point within the file system tree.

              (3)  The file system type.

              (4)  Optional   statistics   and   configuration    information.
                   Currently  (as  at  Linux  2.6.26),  only  NFS file systems
                   export information via this field.

              This file is only readable by the owner of the process.

       /proc/[pid]/ns/ (since Linux 3.0)
              This is a subdirectory containing one entry for  each  namespace
              that  supports  being  manipulated by setns(2).  For information
              about namespaces, see clone(2).

       /proc/[pid]/ns/ipc (since Linux 3.0)
              Bind mounting this file (see mount(2)) to somewhere else in  the
              filesystem  keeps  the IPC namespace of the process specified by
              pid alive even if  all  processes  currently  in  the  namespace
              terminate.

              Opening this file returns a file handle for the IPC namespace of
              the process specified by pid.  As long as this  file  descriptor
              remains  open,  the IPC namespace will remain alive, even if all
              processes in the namespace terminate.  The file  descriptor  can
              be passed to setns(2).

       /proc/[pid]/ns/net (since Linux 3.0)
              Bind  mounting this file (see mount(2)) to somewhere else in the
              filesystem keeps the network namespace of the process  specified
              by pid alive even if all processes in the namespace terminate.

              Opening  this  file  returns  a  file  handle  for  the  network
              namespace of the process specified by pid.  As long as this file
              descriptor  remains  open,  the  network  namespace  will remain
              alive, even if all processes in the  namespace  terminate.   The
              file descriptor can be passed to setns(2).

       /proc/[pid]/ns/uts (since Linux 3.0)
              Bind  mounting this file (see mount(2)) to somewhere else in the
              filesystem keeps the UTS namespace of the process  specified  by
              pid  alive  even  if  all  processes  currently in the namespace
              terminate.

              Opening this file returns a file handle for the UTS namespace of
              the  process  specified by pid.  As long as this file descriptor
              remains open, the UTS namespace will remain alive, even  if  all
              processes  in  the namespace terminate.  The file descriptor can
              be passed to setns(2).

       /proc/[pid]/numa_maps (since Linux 2.6.14)
              See numa(7).

       /proc/[pid]/oom_adj (since Linux 2.6.11)
              This file can be used to adjust the score used to  select  which
              process  should  be  killed in an out-of-memory (OOM) situation.
              The kernel uses this value for  a  bit-shift  operation  of  the
              process's  oom_score value: valid values are in the range -16 to
              +15, plus the special  value  -17,  which  disables  OOM-killing
              altogether  for  this  process.   A positive score increases the
              likelihood of this process being killed  by  the  OOM-killer;  a
              negative  score decreases the likelihood.  The default value for
              this file is 0; a new  process  inherits  its  parent's  oom_adj
              setting.   A  process  must  be privileged (CAP_SYS_RESOURCE) to
              update this file.

       /proc/[pid]/oom_score (since Linux 2.6.11)
              This file displays the current score that the  kernel  gives  to
              this process for the purpose of selecting a process for the OOM-
              killer.  A higher score means that the process is more likely to
              be  selected by the OOM-killer.  The basis for this score is the
              amount of memory used by the  process,  with  increases  (+)  or
              decreases (-) for factors including:

              * whether  the  process  creates a lot of children using fork(2)
                (+);

              * whether the process has been running a long time, or has  used
                a lot of CPU time (-);

              * whether the process has a low nice value (i.e., > 0) (+);

              * whether the process is privileged (-); and

              * whether the process is making direct hardware access (-).

              The  oom_score  also reflects the bit-shift adjustment specified
              by the oom_adj setting for the process.

       /proc/[pid]/root
              UNIX and Linux support the idea of a  per-process  root  of  the
              file  system,  set by the chroot(2) system call.  This file is a
              symbolic link that points to the process's root  directory,  and
              behaves as exe, fd/*, etc. do.

              In  a  multithreaded process, the contents of this symbolic link
              are not available if the  main  thread  has  already  terminated
              (typically by calling pthread_exit(3)).

       /proc/[pid]/smaps (since Linux 2.6.14)
              This  file  shows  memory  consumption for each of the process's
              mappings.  For each of mappings there is a series of lines  such
              as the following:

                  08048000-080bc000 r-xp 00000000 03:02 13130      /bin/bash
                  Size:               464 kB
                  Rss:                424 kB
                  Shared_Clean:       424 kB
                  Shared_Dirty:         0 kB
                  Private_Clean:        0 kB
                  Private_Dirty:        0 kB

              The  first  of  these  lines  shows  the  same information as is
              displayed for the mapping in  /proc/[pid]/maps.   The  remaining
              lines  show  the  size of the mapping, the amount of the mapping
              that is currently resident in RAM, the number of clean and dirty
              shared  pages  in the mapping, and the number of clean and dirty
              private pages in the mapping.

              This file is only present if the CONFIG_MMU kernel configuration
              option is enabled.

       /proc/[pid]/stat
              Status  information  about  the process.  This is used by ps(1).
              It is defined in /usr/src/linux/fs/proc/array.c.

              The  fields,  in  order,  with  their  proper  scanf(3)   format
              specifiers, are:

              pid %d      The process ID.

              comm %s     The  filename  of  the  executable,  in parentheses.
                          This is visible whether or  not  the  executable  is
                          swapped out.

              state %c    One  character  from  the string "RSDZTW" where R is
                          running, S is sleeping in an interruptible  wait,  D
                          is  waiting  in  uninterruptible  disk  sleep,  Z is
                          zombie, T is traced or stopped (on a signal), and  W
                          is paging.

              ppid %d     The PID of the parent.

              pgrp %d     The process group ID of the process.

              session %d  The session ID of the process.

              tty_nr %d   The controlling terminal of the process.  (The minor
                          device number is contained  in  the  combination  of
                          bits 31 to 20 and 7 to 0; the major device number is
                          in bits 15 to 8.)

              tpgid %d    The ID  of  the  foreground  process  group  of  the
                          controlling terminal of the process.

              flags %u (%lu before Linux 2.6.22)
                          The  kernel  flags  word  of  the  process.  For bit
                          meanings, see the PF_* defines  in  <linux/sched.h>.
                          Details depend on the kernel version.

              minflt %lu  The  number  of  minor  faults  the process has made
                          which have not required loading a memory  page  from
                          disk.

              cminflt %lu The  number  of  minor  faults  that  the  process's
                          waited-for children have made.

              majflt %lu  The number of major  faults  the  process  has  made
                          which have required loading a memory page from disk.

              cmajflt %lu The  number  of  major  faults  that  the  process's
                          waited-for children have made.

              utime %lu   Amount of time that this process has been  scheduled
                          in  user  mode,  measured  in clock ticks (divide by
                          sysconf(_SC_CLK_TCK).   This  includes  guest  time,
                          guest_time  (time  spent  running a virtual CPU, see
                          below), so that applications that are not  aware  of
                          the  guest  time  field  do  not lose that time from
                          their calculations.

              stime %lu   Amount of time that this process has been  scheduled
                          in  kernel  mode, measured in clock ticks (divide by
                          sysconf(_SC_CLK_TCK).

              cutime %ld  Amount  of  time  that  this  process's   waited-for
                          children  have been scheduled in user mode, measured
                          in  clock  ticks  (divide  by  sysconf(_SC_CLK_TCK).
                          (See  also  times(2).)   This  includes  guest time,
                          cguest_time (time spent running a virtual  CPU,  see
                          below).

              cstime %ld  Amount   of  time  that  this  process's  waited-for
                          children  have  been  scheduled  in   kernel   mode,
                          measured     in     clock     ticks    (divide    by
                          sysconf(_SC_CLK_TCK).

              priority %ld
                          (Explanation for Linux 2.6) For processes running  a
                          real-time   scheduling  policy  (policy  below;  see
                          sched_setscheduler(2)),   this   is   the    negated
                          scheduling priority, minus one; that is, a number in
                          the range -2 to  -100,  corresponding  to  real-time
                          priorities  1  to 99.  For processes running under a
                          non-real-time scheduling policy,  this  is  the  raw
                          nice  value  (setpriority(2))  as represented in the
                          kernel.  The kernel stores nice values as numbers in
                          the range 0 (high) to 39 (low), corresponding to the
                          user-visible nice range of -20 to 19.

                          Before Linux 2.6, this was a scaled value  based  on
                          the scheduler weighting given to this process.

              nice %ld    The  nice value (see setpriority(2)), a value in the
                          range 19 (low priority) to -20 (high priority).

              num_threads %ld
                          Number of threads in this process (since Linux 2.6).
                          Before kernel 2.6, this field was hard coded to 0 as
                          a placeholder for an earlier removed field.

              itrealvalue %ld
                          The time in jiffies before the next SIGALRM is  sent
                          to  the  process  due  to  an interval timer.  Since
                          kernel 2.6.17, this field is no  longer  maintained,
                          and is hard coded as 0.

              starttime %llu (was %lu before Linux 2.6)
                          The time in jiffies the process started after system
                          boot.

              vsize %lu   Virtual memory size in bytes.

              rss %ld     Resident Set Size: number of pages the  process  has
                          in  real memory.  This is just the pages which count
                          toward text, data, or stack space.   This  does  not
                          include  pages which have not been demand-loaded in,
                          or which are swapped out.

              rsslim %lu  Current soft limit  in  bytes  on  the  rss  of  the
                          process;   see  the  description  of  RLIMIT_RSS  in
                          getpriority(2).

              startcode %lu
                          The address above which program text can run.

              endcode %lu The address below which program text can run.

              startstack %lu
                          The address of  the  start  (i.e.,  bottom)  of  the
                          stack.

              kstkesp %lu The  current  value of ESP (stack pointer), as found
                          in the kernel stack page for the process.

              kstkeip %lu The current EIP (instruction pointer).

              signal %lu  The  bitmap  of  pending  signals,  displayed  as  a
                          decimal  number.   Obsolete,  because  it  does  not
                          provide  information  on  real-time   signals;   use
                          /proc/[pid]/status instead.

              blocked %lu The  bitmap  of  blocked  signals,  displayed  as  a
                          decimal  number.   Obsolete,  because  it  does  not
                          provide   information   on  real-time  signals;  use
                          /proc/[pid]/status instead.

              sigignore %lu
                          The  bitmap  of  ignored  signals,  displayed  as  a
                          decimal  number.   Obsolete,  because  it  does  not
                          provide  information  on  real-time   signals;   use
                          /proc/[pid]/status instead.

              sigcatch %lu
                          The bitmap of caught signals, displayed as a decimal
                          number.   Obsolete,  because  it  does  not  provide
                          information     on     real-time     signals;    use
                          /proc/[pid]/status instead.

              wchan %lu   This is  the  "channel"  in  which  the  process  is
                          waiting.   It  is  the address of a system call, and
                          can be looked up in a namelist if you need a textual
                          name.   (If  you have an up-to-date /etc/psdatabase,
                          then try ps -l to see the WCHAN field in action.)

              nswap %lu   Number of pages swapped (not maintained).

              cnswap %lu  Cumulative   nswap   for   child   processes    (not
                          maintained).

              exit_signal %d (since Linux 2.1.22)
                          Signal to be sent to parent when we die.

              processor %d (since Linux 2.2.8)
                          CPU number last executed on.

              rt_priority %u (since Linux 2.5.19; was %lu before Linux 2.6.22)
                          Real-time scheduling priority, a number in the range
                          1 to 99 for processes scheduled  under  a  real-time
                          policy,  or  0,  for  non-real-time  processes  (see
                          sched_setscheduler(2)).

              policy %u (since Linux 2.5.19; was %lu before Linux 2.6.22)
                          Scheduling   policy   (see   sched_setscheduler(2)).
                          Decode using the SCHED_* constants in linux/sched.h.

              delayacct_blkio_ticks %llu (since Linux 2.6.18)
                          Aggregated block I/O delays, measured in clock ticks
                          (centiseconds).

              guest_time %lu (since Linux 2.6.24)
                          Guest time of the  process  (time  spent  running  a
                          virtual  CPU for a guest operating system), measured
                          in clock ticks (divide by sysconf(_SC_CLK_TCK).

              cguest_time %ld (since Linux 2.6.24)
                          Guest time of the process's  children,  measured  in
                          clock ticks (divide by sysconf(_SC_CLK_TCK).

       /proc/[pid]/statm
              Provides information about memory usage, measured in pages.  The
              columns are:

                  size       total program size
                             (same as VmSize in /proc/[pid]/status)
                  resident   resident set size
                             (same as VmRSS in /proc/[pid]/status)
                  share      shared pages (from shared mappings)
                  text       text (code)
                  lib        library (unused in Linux 2.6)
                  data       data + stack
                  dt         dirty pages (unused in Linux 2.6)

       /proc/[pid]/status
              Provides  much  of  the  information  in  /proc/[pid]/stat   and
              /proc/[pid]/statm in a format that's easier for humans to parse.
              Here's an example:

                  $ cat /proc/$$/status
                  Name:   bash
                  State:  S (sleeping)
                  Tgid:   3515
                  Pid:    3515
                  PPid:   3452
                  TracerPid:      0
                  Uid:    1000    1000    1000    1000
                  Gid:    100     100     100     100
                  FDSize: 256
                  Groups: 16 33 100
                  VmPeak:     9136 kB
                  VmSize:     7896 kB
                  VmLck:         0 kB
                  VmHWM:      7572 kB
                  VmRSS:      6316 kB
                  VmData:     5224 kB
                  VmStk:        88 kB
                  VmExe:       572 kB
                  VmLib:      1708 kB
                  VmPTE:        20 kB
                  Threads:        1
                  SigQ:   0/3067
                  SigPnd: 0000000000000000
                  ShdPnd: 0000000000000000
                  SigBlk: 0000000000010000
                  SigIgn: 0000000000384004
                  SigCgt: 000000004b813efb
                  CapInh: 0000000000000000
                  CapPrm: 0000000000000000
                  CapEff: 0000000000000000
                  CapBnd: ffffffffffffffff
                  Cpus_allowed:   00000001
                  Cpus_allowed_list:      0
                  Mems_allowed:   1
                  Mems_allowed_list:      0
                  voluntary_ctxt_switches:        150
                  nonvoluntary_ctxt_switches:     545

              The fields are as follows:

              * Name: Command run by this process.

              * State: Current state of the process.  One of "R (running)", "S
                (sleeping)",  "D  (disk  sleep)",  "T  (stopped)", "T (tracing
                stop)", "Z (zombie)", or "X (dead)".

              * Tgid: Thread group ID (i.e., Process ID).

              * Pid: Thread ID (see gettid(2)).

              * PPid: PID of parent process.

              * TracerPid: PID of process tracing this process (0 if not being
                traced).

              * Uid,  Gid:  Real,  effective,  saved set, and file system UIDs
                (GIDs).

              * FDSize: Number of file descriptor slots currently allocated.

              * Groups: Supplementary group list.

              * VmPeak: Peak virtual memory size.

              * VmSize: Virtual memory size.

              * VmLck: Locked memory size (see mlock(3)).

              * VmHWM: Peak resident set size ("high water mark").

              * VmRSS: Resident set size.

              * VmData, VmStk, VmExe: Size of data, stack, and text segments.

              * VmLib: Shared library code size.

              * VmPTE: Page table entries size (since Linux 2.6.10).

              * Threads: Number of threads in process containing this thread.

              * SigQ: This field contains  two  slash-separated  numbers  that
                relate to queued signals for the real user ID of this process.
                The first of these is the number of currently  queued  signals
                for this real user ID, and the second is the resource limit on
                the number  of  queued  signals  for  this  process  (see  the
                description of RLIMIT_SIGPENDING in getrlimit(2)).

              * SigPnd,  ShdPnd:  Number of signals pending for thread and for
                process as a whole (see pthreads(7) and signal(7)).

              * SigBlk,  SigIgn,  SigCgt:  Masks  indicating   signals   being
                blocked, ignored, and caught (see signal(7)).

              * CapInh,  CapPrm,  CapEff:  Masks  of  capabilities  enabled in
                inheritable,    permitted,    and    effective    sets    (see
                capabilities(7)).

              * CapBnd:  Capability  Bounding  set  (since  kernel 2.6.26, see
                capabilities(7)).

              * Cpus_allowed: Mask of CPUs  on  which  this  process  may  run
                (since Linux 2.6.24, see cpuset(7)).

              * Cpus_allowed_list:  Same  as  previous,  but  in "list format"
                (since Linux 2.6.26, see cpuset(7)).

              * Mems_allowed: Mask of memory nodes  allowed  to  this  process
                (since Linux 2.6.24, see cpuset(7)).

              * Mems_allowed_list:  Same  as  previous,  but  in "list format"
                (since Linux 2.6.26, see cpuset(7)).

              * voluntary_context_switches,     nonvoluntary_context_switches:
                Number  of  voluntary  and involuntary context switches (since
                Linux 2.6.23).

       /proc/[pid]/task (since Linux 2.6.0-test6)
              This is a directory that  contains  one  subdirectory  for  each
              thread  in  the  process.   The name of each subdirectory is the
              numerical thread ID  ([tid])  of  the  thread  (see  gettid(2)).
              Within  each  of  these  subdirectories, there is a set of files
              with the same  names  and  contents  as  under  the  /proc/[pid]
              directories.  For attributes that are shared by all threads, the
              contents  for  each  of   the   files   under   the   task/[tid]
              subdirectories  will be the same as in the corresponding file in
              the parent  /proc/[pid]  directory  (e.g.,  in  a  multithreaded
              process,  all  of  the  task/[tid]/cwd  files will have the same
              value as the /proc/[pid]/cwd file in the parent directory, since
              all of the threads in a process share a working directory).  For
              attributes that are distinct for each thread, the  corresponding
              files  under task/[tid] may have different values (e.g., various
              fields in each of the task/[tid]/status files may  be  different
              for each thread).

              In a multithreaded process, the contents of the /proc/[pid]/task
              directory are not available  if  the  main  thread  has  already
              terminated (typically by calling pthread_exit(3)).

       /proc/apm
              Advanced  power  management version and battery information when
              CONFIG_APM is defined at kernel compilation time.

       /proc/bus
              Contains subdirectories for installed busses.

       /proc/bus/pccard
              Subdirectory for PCMCIA devices when  CONFIG_PCMCIA  is  set  at
              kernel compilation time.

       /proc/bus/pccard/drivers

       /proc/bus/pci
              Contains  various bus subdirectories and pseudo-files containing
              information about PCI  busses,  installed  devices,  and  device
              drivers.  Some of these files are not ASCII.

       /proc/bus/pci/devices
              Information  about  PCI  devices.   They may be accessed through
              lspci(8) and setpci(8).

       /proc/cmdline
              Arguments passed to the Linux kernel at boot time.   Often  done
              via a boot manager such as lilo(8) or grub(8).

       /proc/config.gz (since Linux 2.6)
              This  file  exposes  the configuration options that were used to
              build the currently running kernel, in the same format  as  they
              would   be   shown  in  the  .config  file  that  resulted  when
              configuring the kernel (using  make  xconfig,  make  config,  or
              similar).  The file contents are compressed; view or search them
              using zcat(1), zgrep(1), etc.  As long as no changes  have  been
              made  to the following file, the contents of /proc/config.gz are
              the same as those provided by :

                  cat /lib/modules/$(uname -r)/build/.config

              /proc/config.gz is only provided if  the  kernel  is  configured
              with CONFIG_IKCONFIG_PROC.

       /proc/cpuinfo
              This  is  a  collection of CPU and system architecture dependent
              items, for each supported architecture a  different  list.   Two
              common   entries  are  processor  which  gives  CPU  number  and
              bogomips; a system constant that  is  calculated  during  kernel
              initialization.  SMP machines have information for each CPU.

       /proc/devices
              Text  listing  of  major numbers and device groups.  This can be
              used by MAKEDEV scripts for consistency with the kernel.

       /proc/diskstats (since Linux 2.5.69)
              This file contains disk I/O statistics  for  each  disk  device.
              See the kernel source file Documentation/iostats.txt for further
              information.

       /proc/dma
              This is a list of the registered ISA DMA (direct memory  access)
              channels in use.

       /proc/driver
              Empty subdirectory.

       /proc/execdomains
              List of the execution domains (ABI personalities).

       /proc/fb
              Frame buffer information when CONFIG_FB is defined during kernel
              compilation.

       /proc/filesystems
              A text listing of the file systems which are  supported  by  the
              kernel,  namely file systems which were compiled into the kernel
              or  whose  kernel  modules  are  currently  loaded.   (See  also
              filesystems(5).)   If a file system is marked with "nodev", this
              means that it does not require a  block  device  to  be  mounted
              (e.g., virtual file system, network file system).

              Incidentally,  this  file  may  be used by mount(8) when no file
              system is specified and it didn't manage to determine  the  file
              system type.  Then file systems contained in this file are tried
              (excepted those that are marked with "nodev").

       /proc/fs
              Empty subdirectory.

       /proc/ide
              This directory exists on systems with the IDE  bus.   There  are
              directories  for  each  IDE  channel and attached device.  Files
              include:

                  cache              buffer size in KB
                  capacity           number of sectors
                  driver             driver version
                  geometry           physical and logical geometry
                  identify           in hexadecimal
                  media              media type
                  model              manufacturer's model number
                  settings           drive settings
                  smart_thresholds   in hexadecimal
                  smart_values       in hexadecimal

              The hdparm(8) utility provides access to this information  in  a
              friendly format.

       /proc/interrupts
              This  is  used to record the number of interrupts per CPU per IO
              device.   Since  Linux  2.6.24,  for   the   i386   and   x86_64
              architectures,  at least, this also includes interrupts internal
              to the system (that is, not associated with a device  as  such),
              such   as   NMI   (nonmaskable   interrupt),  LOC  (local  timer
              interrupt), and for SMP systems, TLB (TLB flush interrupt),  RES
              (rescheduling  interrupt), CAL (remote function call interrupt),
              and possibly others.  Very easy  to  read  formatting,  done  in
              ASCII.

       /proc/iomem
              I/O memory map in Linux 2.4.

       /proc/ioports
              This is a list of currently registered Input-Output port regions
              that are in use.

       /proc/kallsyms (since Linux 2.5.71)
              This holds the kernel exported symbol definitions  used  by  the
              modules(X)  tools to dynamically link and bind loadable modules.
              In Linux 2.5.47  and  earlier,  a  similar  file  with  slightly
              different syntax was named ksyms.

       /proc/kcore
              This  file  represents  the physical memory of the system and is
              stored in the ELF core file format.  With this pseudo-file,  and
              an unstripped kernel (/usr/src/linux/vmlinux) binary, GDB can be
              used to examine the current state of any kernel data structures.

              The total length of the file is  the  size  of  physical  memory
              (RAM) plus 4KB.

       /proc/kmsg
              This  file  can  be used instead of the syslog(2) system call to
              read kernel messages.  A process must have superuser  privileges
              to  read  this file, and only one process should read this file.
              This file should not be read if  a  syslog  process  is  running
              which  uses  the  syslog(2)  system  call facility to log kernel
              messages.

              Information in this file is retrieved with the dmesg(1) program.

       /proc/ksyms (Linux 1.1.23-2.5.47)
              See /proc/kallsyms.

       /proc/loadavg
              The first three fields in this file  are  load  average  figures
              giving  the number of jobs in the run queue (state R) or waiting
              for disk I/O (state D) averaged over 1, 5, and 15 minutes.  They
              are  the same as the load average numbers given by uptime(1) and
              other programs.   The  fourth  field  consists  of  two  numbers
              separated  by  a slash (/).  The first of these is the number of
              currently  executing  kernel  scheduling  entities   (processes,
              threads); this will be less than or equal to the number of CPUs.
              The value after the slash is the  number  of  kernel  scheduling
              entities that currently exist on the system.  The fifth field is
              the PID of the process that was most  recently  created  on  the
              system.

       /proc/locks
              This  file  shows current file locks (flock(2) and fcntl(2)) and
              leases (fcntl(2)).

       /proc/malloc (only up to and including Linux 2.2)
              This file is only present  if  CONFIG_DEBUG_MALLOC  was  defined
              during compilation.

       /proc/meminfo
              This  file  reports statistics about memory usage on the system.
              It is used by free(1) to report the  amount  of  free  and  used
              memory  (both  physical  and  swap) on the system as well as the
              shared memory and buffers used by the kernel.

       /proc/modules
              A text list of the modules that have been loaded by the  system.
              See also lsmod(8).

       /proc/mounts
              Before  kernel  2.4.19,  this  file  was  a list of all the file
              systems currently mounted on the system.  With the  introduction
              of  per-process  mount  namespaces  in  Linux  2.4.19, this file
              became a link to /proc/self/mounts, which lists the mount points
              of  the  process's own mount namespace.  The format of this file
              is documented in fstab(5).

       /proc/mtrr
              Memory  Type  Range  Registers.   See  the  kernel  source  file
              Documentation/mtrr.txt for details.

       /proc/net
              various  net  pseudo-files, all of which give the status of some
              part  of  the  networking  layer.   These  files  contain  ASCII
              structures  and  are, therefore, readable with cat(1).  However,
              the standard netstat(8) suite provides much  cleaner  access  to
              these files.

       /proc/net/arp
              This  holds  an ASCII readable dump of the kernel ARP table used
              for address resolutions.  It will show both dynamically  learned
              and preprogrammed ARP entries.  The format is:

        IP address     HW type   Flags     HW address          Mask   Device
        192.168.0.50   0x1       0x2       00:50:BF:25:68:F3   *      eth0
        192.168.0.250  0x1       0xc       00:00:00:00:00:00   *      eth0

              Here "IP address" is the IPv4 address of the machine and the "HW
              type" is the hardware type of the  address  from  RFC 826.   The
              flags are the internal flags of the ARP structure (as defined in
              /usr/include/linux/if_arp.h) and the "HW address"  is  the  data
              link layer mapping for that IP address if it is known.

       /proc/net/dev
              The  dev pseudo-file contains network device status information.
              This gives the number of received and sent packets,  the  number
              of  errors and collisions and other basic statistics.  These are
              used by the ifconfig(8) program to report  device  status.   The
              format is:

 Inter-|   Receive                                                |  Transmit
  face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
     lo: 2776770   11307    0    0    0     0          0         0  2776770   11307    0    0    0     0       0          0
   eth0: 1215645    2751    0    0    0     0          0         0  1782404    4324    0    0    0   427       0          0
   ppp0: 1622270    5552    1    0    0     0          0         0   354130    5669    0    0    0     0       0          0
   tap0:    7714      81    0    0    0     0          0         0     7714      81    0    0    0     0       0          0

       /proc/net/dev_mcast
              Defined in /usr/src/linux/net/core/dev_mcast.c:
                   indx interface_name  dmi_u dmi_g dmi_address
                   2    eth0            1     0     01005e000001
                   3    eth1            1     0     01005e000001
                   4    eth2            1     0     01005e000001

       /proc/net/igmp
              Internet     Group     Management    Protocol.     Defined    in
              /usr/src/linux/net/core/igmp.c.

       /proc/net/rarp
              This file uses the same format as the arp file and contains  the
              current reverse mapping database used to provide rarp(8) reverse
              address lookup services.  If RARP is  not  configured  into  the
              kernel, this file will not be present.

       /proc/net/raw
              Holds  a  dump of the RAW socket table.  Much of the information
              is not of use apart from  debugging.   The  "sl"  value  is  the
              kernel  hash  slot  for  the  socket, the "local_address" is the
              local address and protocol number pair.  "St"  is  the  internal
              status  of  the  socket.   The "tx_queue" and "rx_queue" are the
              outgoing and incoming data  queue  in  terms  of  kernel  memory
              usage.   The "tr", "tm->when", and "rexmits" fields are not used
              by RAW.  The "uid" field holds the effective UID of the  creator
              of the socket.

       /proc/net/snmp
              This file holds the ASCII data needed for the IP, ICMP, TCP, and
              UDP management information bases for an SNMP agent.

       /proc/net/tcp
              Holds a dump of the TCP socket table.  Much of  the  information
              is  not  of  use  apart  from  debugging.  The "sl" value is the
              kernel hash slot for the  socket,  the  "local_address"  is  the
              local  address  and  port number pair.  The "rem_address" is the
              remote address and port number pair (if connected).  "St" is the
              internal  status  of  the socket.  The "tx_queue" and "rx_queue"
              are the outgoing and incoming data  queue  in  terms  of  kernel
              memory  usage.   The "tr", "tm->when", and "rexmits" fields hold
              internal information of the kernel socket  state  and  are  only
              useful  for  debugging.  The "uid" field holds the effective UID
              of the creator of the socket.

       /proc/net/udp
              Holds a dump of the UDP socket table.  Much of  the  information
              is  not  of  use  apart  from  debugging.  The "sl" value is the
              kernel hash slot for the  socket,  the  "local_address"  is  the
              local  address  and  port number pair.  The "rem_address" is the
              remote address and port number pair (if connected). "St" is  the
              internal  status  of  the socket.  The "tx_queue" and "rx_queue"
              are the outgoing and incoming data  queue  in  terms  of  kernel
              memory  usage.   The  "tr", "tm->when", and "rexmits" fields are
              not used by UDP.  The "uid" field holds the effective UID of the
              creator of the socket.  The format is:

 sl  local_address rem_address   st tx_queue rx_queue tr rexmits  tm->when uid
  1: 01642C89:0201 0C642C89:03FF 01 00000000:00000001 01:000071BA 00000000 0
  1: 00000000:0801 00000000:0000 0A 00000000:00000000 00:00000000 6F000100 0
  1: 00000000:0201 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0

       /proc/net/unix
              Lists  the  UNIX  domain  sockets  present within the system and
              their status.  The format is:
              Num RefCount Protocol Flags    Type St Path
               0: 00000002 00000000 00000000 0001 03
               1: 00000001 00000000 00010000 0001 01 /dev/printer

              Here "Num" is the kernel table slot number,  "RefCount"  is  the
              number of users of the socket, "Protocol" is currently always 0,
              "Flags" represent the internal kernel flags holding  the  status
              of  the  socket.   Currently,  type  is  always "1" (UNIX domain
              datagram sockets are not yet supported in the kernel).  "St"  is
              the  internal state of the socket and Path is the bound path (if
              any) of the socket.

       /proc/partitions
              Contains major and minor numbers of each partition  as  well  as
              number of blocks and partition name.

       /proc/pci
              This  is  a  listing  of  all  PCI  devices  found during kernel
              initialization and their configuration.

              This file has been deprecated in favor of a new /proc  interface
              for  PCI  (/proc/bus/pci).   It  became  optional  in  Linux 2.2
              (available with CONFIG_PCI_OLD_PROC set at kernel  compilation).
              It  became  once more nonoptionally enabled in Linux 2.4.  Next,
              it  was  deprecated  in  Linux   2.6   (still   available   with
              CONFIG_PCI_LEGACY_PROC  set),  and  finally  removed  altogether
              since Linux 2.6.17.

       /proc/scsi
              A directory with the scsi mid-level pseudo-file and various SCSI
              low-level driver directories, which contain a file for each SCSI
              host in this system, all of which give the status of  some  part
              of  the SCSI IO subsystem.  These files contain ASCII structures
              and are, therefore, readable with cat(1).

              You can also write to some  of  the  files  to  reconfigure  the
              subsystem or switch certain features on or off.

       /proc/scsi/scsi
              This  is a listing of all SCSI devices known to the kernel.  The
              listing  is  similar  to  the  one  seen  during  bootup.   scsi
              currently  supports  only  the  add-single-device  command which
              allows root to add a hotplugged device  to  the  list  of  known
              devices.

              The command

                  echo 'scsi add-single-device 1 0 5 0' > /proc/scsi/scsi

              will  cause host scsi1 to scan on SCSI channel 0 for a device on
              ID 5 LUN 0.  If there is already a device known on this  address
              or the address is invalid, an error will be returned.

       /proc/scsi/[drivername]
              [drivername]  can  currently  be  NCR53c7xx,  aha152x,  aha1542,
              aha1740, aic7xxx, buslogic, eata_dma, eata_pio, fdomain, in2000,
              pas16,  qlogic,  scsi_debug, seagate, t128, u15-24f, ultrastore,
              or wd7000.  These directories  show  up  for  all  drivers  that
              registered  at least one SCSI HBA.  Every directory contains one
              file per registered host.  Every host-file is  named  after  the
              number the host was assigned during initialization.

              Reading   these   files   will  usually  show  driver  and  host
              configuration, statistics, etc.

              Writing to these files  allows  different  things  on  different
              hosts.   For  example,  with the latency and nolatency commands,
              root can switch on and off command latency measurement  code  in
              the  eata_dma driver.  With the lockup and unlock commands, root
              can control bus lockups simulated by the scsi_debug driver.

       /proc/self
              This directory refers to the process accessing  the  /proc  file
              system,  and  is  identical  to the /proc directory named by the
              process ID of the same process.

       /proc/slabinfo
              Information about kernel caches.  Since Linux 2.6.16  this  file
              is  only  present if the CONFIG_SLAB kernel configuration option
              is enabled.  The columns in /proc/slabinfo are:

                  cache-name
                  num-active-objs
                  total-objs
                  object-size
                  num-active-slabs
                  total-slabs
                  num-pages-per-slab

              See slabinfo(5) for details.

       /proc/stat
              kernel/system statistics.   Varies  with  architecture.   Common
              entries include:

              cpu  3357 0 4313 1362393
                     The   amount  of  time,  measured  in  units  of  USER_HZ
                     (1/100ths  of  a  second  on  most   architectures,   use
                     sysconf(_SC_CLK_TCK) to obtain the right value), that the
                     system spent in user mode, user mode  with  low  priority
                     (nice),  system  mode,  and  the idle task, respectively.
                     The last value should be USER_HZ times the  second  entry
                     in the uptime pseudo-file.

                     In Linux 2.6 this line includes three additional columns:
                     iowait - time waiting for I/O to complete (since 2.5.41);
                     irq  -  time  servicing  interrupts  (since 2.6.0-test4);
                     softirq - time servicing softirqs (since 2.6.0-test4).

                     Since Linux 2.6.11, there is an eighth  column,  steal  -
                     stolen  time,  which is the time spent in other operating
                     systems when running in a virtualized environment

                     Since Linux 2.6.24, there is a ninth column, guest, which
                     is  the  time  spent  running  a  virtual  CPU  for guest
                     operating systems under the control of the Linux kernel.

              page 5741 1808
                     The number of pages the system paged in  and  the  number
                     that were paged out (from disk).

              swap 1 0
                     The  number  of  swap pages that have been brought in and
                     out.

              intr 1462898
                     This line shows counts of interrupts serviced since  boot
                     time,  for  each  of the possible system interrupts.  The
                     first column is the total  of  all  interrupts  serviced;
                     each  subsequent  column  is  the  total for a particular
                     interrupt.

              disk_io: (2,0):(31,30,5764,1,2) (3,0):...
                     (major,disk_idx):(noinfo,     read_io_ops,     blks_read,
                     write_io_ops, blks_written)
                     (Linux 2.4 only)

              ctxt 115315
                     The number of context switches that the system underwent.

              btime 769041601
                     boot   time,  in  seconds  since  the  Epoch,  1970-01-01
                     00:00:00 +0000 (UTC).

              processes 86031
                     Number of forks since boot.

              procs_running 6
                     Number of processes in  runnable  state.   (Linux  2.5.45
                     onward.)

              procs_blocked 2
                     Number  of processes blocked waiting for I/O to complete.
                     (Linux 2.5.45 onward.)

       /proc/swaps
              Swap areas in use.  See also swapon(8).

       /proc/sys
              This directory (present since 1.3.57) contains a number of files
              and  subdirectories  corresponding  to  kernel variables.  These
              variables can be read and sometimes  modified  using  the  /proc
              file system, and the (deprecated) sysctl(2) system call.

       /proc/sys/abi (since Linux 2.4.10)
              This   directory  may  contain  files  with  application  binary
              information.      See      the      kernel      source      file
              Documentation/sysctl/abi.txt for more information.

       /proc/sys/debug
              This directory may be empty.

       /proc/sys/dev
              This   directory  contains  device-specific  information  (e.g.,
              dev/cdrom/info).  On some systems, it may be empty.

       /proc/sys/fs
              This directory contains the files and subdirectories for  kernel
              variables related to file systems.

       /proc/sys/fs/binfmt_misc
              Documentation  for  files  in this directory can be found in the
              kernel sources in Documentation/binfmt_misc.txt.

       /proc/sys/fs/dentry-state (since Linux 2.2)
              This file contains information about the status of the directory
              cache  (dcache).   The  file  contains  six  numbers, nr_dentry,
              nr_unused,  age_limit  (age  in  seconds),   want_pages   (pages
              requested by system) and two dummy values.

              * nr_dentry   is   the  number  of  allocated  dentries  (dcache
                entries).  This field is unused in Linux 2.2.

              * nr_unused is the number of unused dentries.

              * age_limit is the age in seconds after which dcache entries can
                be reclaimed when memory is short.

              * want_pages   is   nonzero   when   the   kernel   has   called
                shrink_dcache_pages() and the dcache isn't pruned yet.

       /proc/sys/fs/dir-notify-enable
              This file can be used to disable or enable the dnotify interface
              described  in  fcntl(2) on a system-wide basis.  A value of 0 in
              this file disables the interface, and a value of 1 enables it.

       /proc/sys/fs/dquot-max
              This file shows the maximum number of cached disk quota entries.
              On some (2.4) systems, it is not present.  If the number of free
              cached disk quota entries is very low and you have some  awesome
              number of simultaneous system users, you might want to raise the
              limit.

       /proc/sys/fs/dquot-nr
              This file shows the number of allocated disk quota  entries  and
              the number of free disk quota entries.

       /proc/sys/fs/epoll (since Linux 2.6.28)
              This  directory contains the file max_user_watches, which can be
              used to limit the amount of kernel memory consumed by the  epoll
              interface.  For further details, see epoll(7).

       /proc/sys/fs/file-max
              This  file  defines  a  system-wide  limit on the number of open
              files for all processes.  (See also setrlimit(2), which  can  be
              used  by  a process to set the per-process limit, RLIMIT_NOFILE,
              on the number of files it may open.)  If you get lots  of  error
              messages  about running out of file handles, try increasing this
              value:

              echo 100000 > /proc/sys/fs/file-max

              The kernel constant NR_OPEN imposes an upper limit on the  value
              that may be placed in file-max.

              If  you  increase  /proc/sys/fs/file-max,  be  sure  to increase
              /proc/sys/fs/inode-max  to  3-4   times   the   new   value   of
              /proc/sys/fs/file-max, or you will run out of inodes.

       /proc/sys/fs/file-nr
              This  (read-only)  file  gives  the  number  of  files presently
              opened.  It contains three numbers: the number of allocated file
              handles; the number of free file handles; and the maximum number
              of file handles.  The kernel allocates file handles dynamically,
              but  it  doesn't  free  them  again.  If the number of allocated
              files is close to the maximum, you  should  consider  increasing
              the  maximum.   When  the  number of free file handles is large,
              you've encountered a peak in your usage of file handles and  you
              probably don't need to increase the maximum.

       /proc/sys/fs/inode-max
              This  file  contains the maximum number of in-memory inodes.  On
              some (2.4) systems, it may not be present.  This value should be
              3-4 times larger than the value in file-max, since stdin, stdout
              and network sockets also need an inode to handle them.  When you
              regularly run out of inodes, you need to increase this value.

       /proc/sys/fs/inode-nr
              This file contains the first two values from inode-state.

       /proc/sys/fs/inode-state
              This  file  contains  seven  numbers: nr_inodes, nr_free_inodes,
              preshrink, and four dummy values.  nr_inodes is  the  number  of
              inodes the system has allocated.  This can be slightly more than
              inode-max because Linux allocates them one page full at a  time.
              nr_free_inodes  represents the number of free inodes.  preshrink
              is nonzero when the nr_inodes > inode-max and the  system  needs
              to prune the inode list instead of allocating more.

       /proc/sys/fs/inotify (since Linux 2.6.13)
              This     directory     contains     files     max_queued_events,
              max_user_instances, and max_user_watches, that can  be  used  to
              limit  the  amount  of  kernel  memory  consumed  by the inotify
              interface.  For further details, see inotify(7).

       /proc/sys/fs/lease-break-time
              This file specifies the grace period that the kernel grants to a
              process  holding  a  file  lease  (fcntl(2)) after it has sent a
              signal to that process notifying  it  that  another  process  is
              waiting  to  open the file.  If the lease holder does not remove
              or downgrade the lease within  this  grace  period,  the  kernel
              forcibly breaks the lease.

       /proc/sys/fs/leases-enable
              This  file  can  be  used  to  enable  or  disable  file  leases
              (fcntl(2)) on a system-wide basis.  If this  file  contains  the
              value 0, leases are disabled.  A nonzero value enables leases.

       /proc/sys/fs/mqueue (since Linux 2.6.6)
              This   directory   contains   files  msg_max,  msgsize_max,  and
              queues_max, controlling the  resources  used  by  POSIX  message
              queues.  See mq_overview(7) for details.

       /proc/sys/fs/overflowgid and /proc/sys/fs/overflowuid
              These  files  allow you to change the value of the fixed UID and
              GID.  The default is 65534.   Some  file  systems  only  support
              16-bit  UIDs  and  GIDs,  although in Linux UIDs and GIDs are 32
              bits.  When one of these file systems  is  mounted  with  writes
              enabled, any UID or GID that would exceed 65535 is translated to
              the overflow value before being written to disk.

       /proc/sys/fs/pipe-max-size (since Linux 2.6.35)
              The value in this file defines an upper limit  for  raising  the
              capacity  of  a  pipe using the fcntl(2) F_SETPIPE_SZ operation.
              This limit applies only to unprivileged processes.  The  default
              value  for  this  file is 1,048,576.  The value assigned to this
              file may be  rounded  upward,  to  reflect  the  value  actually
              employed  for  a  convenient  implementation.   To determine the
              rounded-up value,  display  the  contents  of  this  file  after
              assigning a value to it.  The minimum value that can be assigned
              to this file is the system page size.

       /proc/sys/fs/suid_dumpable (since Linux 2.6.13)
              The value in this file determines whether core  dump  files  are
              produced   for   set-user-ID   or   otherwise  protected/tainted
              binaries.  Three different integer values can be specified:

              0 (default) This provides  the  traditional  (pre-Linux  2.6.13)
              behavior.   A core dump will not be produced for a process which
              has changed credentials (by calling  seteuid(2),  setgid(2),  or
              similar,  or by executing a set-user-ID or set-group-ID program)
              or whose binary does not have read permission enabled.

              1 ("debug") All processes dump core  when  possible.   The  core
              dump  is owned by the file system user ID of the dumping process
              and no  security  is  applied.   This  is  intended  for  system
              debugging situations only.  Ptrace is unchecked.

              2 ("suidsafe")  Any  binary  which  normally would not be dumped
              (see "0" above) is dumped readable by root  only.   This  allows
              the  user  to remove the core dump file but not to read it.  For
              security reasons core dumps in this mode will not overwrite  one
              another   or   other  files.   This  mode  is  appropriate  when
              administrators are attempting to  debug  problems  in  a  normal
              environment.

       /proc/sys/fs/super-max
              This  file  controls the maximum number of superblocks, and thus
              the maximum number of mounted file systems the kernel can  have.
              You  only  need  to increase super-max if you need to mount more
              file systems than the current value in super-max allows you to.

       /proc/sys/fs/super-nr
              This file contains the number of file systems currently mounted.

       /proc/sys/kernel
              This directory contains files  controlling  a  range  of  kernel
              parameters, as described below.

       /proc/sys/kernel/acct
              This  file  contains  three  numbers:  highwater,  lowwater, and
              frequency.  If BSD-style process  accounting  is  enabled  these
              values control its behavior.  If free space on file system where
              the log lives goes below lowwater percent  accounting  suspends.
              If  free  space gets above highwater percent accounting resumes.
              frequency determines how often the kernel checks the  amount  of
              free  space  (value is in seconds).  Default values are 4, 2 and
              30.  That is, suspend accounting if 2% or less  space  is  free;
              resume  it  if  4%  or  more space is free; consider information
              about amount of free space valid for 30 seconds.

       /proc/sys/kernel/cap-bound (from Linux 2.2 to 2.6.24)
              This file holds the value of the kernel capability bounding  set
              (expressed  as  a  signed  decimal  number).   This set is ANDed
              against  the  capabilities  permitted  to   a   process   during
              execve(2).    Starting   with   Linux  2.6.25,  the  system-wide
              capability bounding set disappeared, and was replaced by a  per-
              thread bounding set; see capabilities(7).

       /proc/sys/kernel/core_pattern
              See core(5).

       /proc/sys/kernel/core_uses_pid
              See core(5).

       /proc/sys/kernel/ctrl-alt-del
              This  file  controls  the  handling  of  Ctrl-Alt-Del  from  the
              keyboard.  When the value in this file  is  0,  Ctrl-Alt-Del  is
              trapped  and  sent  to  the init(8) program to handle a graceful
              restart.  When the value is greater than zero, Linux's  reaction
              to  a  Vulcan  Nerve  Pinch  (tm)  will  be an immediate reboot,
              without even syncing its dirty buffers.  Note:  when  a  program
              (like  dosemu)  has the keyboard in "raw" mode, the ctrl-alt-del
              is intercepted by the program before it ever reaches the  kernel
              tty  layer, and it's up to the program to decide what to do with
              it.

       /proc/sys/kernel/hotplug
              This file contains the path for the hotplug policy  agent.   The
              default value in this file is /sbin/hotplug.

       /proc/sys/kernel/domainname and /proc/sys/kernel/hostname
              can  be  used  to  set the NIS/YP domainname and the hostname of
              your box in exactly the same way as the  commands  domainname(1)
              and hostname(1), that is:

                  # echo 'darkstar' > /proc/sys/kernel/hostname
                  # echo 'mydomain' > /proc/sys/kernel/domainname

              has the same effect as

                  # hostname 'darkstar'
                  # domainname 'mydomain'

              Note,  however,  that  the  classic  darkstar.frop.org  has  the
              hostname  "darkstar"  and  DNS  (Internet  Domain  Name  Server)
              domainname  "frop.org", not to be confused with the NIS (Network
              Information Service) or YP (Yellow Pages) domainname.  These two
              domain   names   are  in  general  different.   For  a  detailed
              discussion see the hostname(1) man page.

       /proc/sys/kernel/htab-reclaim
              (PowerPC only) If this file is  set  to  a  nonzero  value,  the
              PowerPC          htab          (see          kernel         file
              Documentation/powerpc/ppc_htab.txt)  is  pruned  each  time  the
              system hits the idle loop.

       /proc/sys/kernel/l2cr
              (PowerPC  only)  This  file contains a flag that controls the L2
              cache of G3 processor boards.  If  0,  the  cache  is  disabled.
              Enabled if nonzero.

       /proc/sys/kernel/modprobe
              This  file  contains the path for the kernel module loader.  The
              default value is /sbin/modprobe.  The file is  only  present  if
              the  kernel is built with the CONFIG_KMOD option enabled.  It is
              described by the kernel source file Documentation/kmod.txt (only
              present in kernel 2.4 and earlier).

       /proc/sys/kernel/msgmax
              This  file  defines  a  system-wide limit specifying the maximum
              number of bytes in a  single  message  written  on  a  System  V
              message queue.

       /proc/sys/kernel/msgmni
              This file defines the system-wide limit on the number of message
              queue identifiers.  (This file is  only  present  in  Linux  2.4
              onward.)

       /proc/sys/kernel/msgmnb
              This file defines a system-wide parameter used to initialize the
              msg_qbytes setting for subsequently created message queues.  The
              msg_qbytes  setting  specifies  the maximum number of bytes that
              may be written to the message queue.

       /proc/sys/kernel/ostype and /proc/sys/kernel/osrelease
              These files give substrings of /proc/version.

       /proc/sys/kernel/overflowgid and /proc/sys/kernel/overflowuid
              These files duplicate  the  files  /proc/sys/fs/overflowgid  and
              /proc/sys/fs/overflowuid.

       /proc/sys/kernel/panic
              This  file  gives  read/write  access  to  the  kernel  variable
              panic_timeout.  If this is zero,  the  kernel  will  loop  on  a
              panic; if nonzero it indicates that the kernel should autoreboot
              after this  number  of  seconds.   When  you  use  the  software
              watchdog device driver, the recommended setting is 60.

       /proc/sys/kernel/panic_on_oops (since Linux 2.5.68)
              This  file controls the kernel's behavior when an oops or BUG is
              encountered.  If this file contains 0, then the system tries  to
              continue  operation.  If it contains 1, then the system delays a
              few seconds (to give klogd time to record the oops  output)  and
              then panics.  If the /proc/sys/kernel/panic file is also nonzero
              then the machine will be rebooted.

       /proc/sys/kernel/pid_max (since Linux 2.5.34)
              This file specifies the value at which PIDs wrap  around  (i.e.,
              the  value  in  this  file is one greater than the maximum PID).
              The default value for this file,  32768,  results  in  the  same
              range of PIDs as on earlier kernels.  On 32-bit platforms, 32768
              is the maximum value for pid_max.  On  64-bit  systems,  pid_max
              can be set to any value up to 2^22 (PID_MAX_LIMIT, approximately
              4 million).

       /proc/sys/kernel/powersave-nap (PowerPC only)
              This file contains a flag.  If set, Linux-PPC will use the "nap"
              mode of powersaving, otherwise the "doze" mode will be used.

       /proc/sys/kernel/printk
              The   four   values   in   this   file   are   console_loglevel,
              default_message_loglevel,       minimum_console_level,       and
              default_console_loglevel.    These   values  influence  printk()
              behavior when printing or logging error messages.  See syslog(2)
              for  more  info  on  the  different  loglevels.  Messages with a
              higher priority than console_loglevel will  be  printed  to  the
              console.   Messages without an explicit priority will be printed
              with priority  default_message_level.   minimum_console_loglevel
              is  the minimum (highest) value to which console_loglevel can be
              set.   default_console_loglevel  is  the   default   value   for
              console_loglevel.

       /proc/sys/kernel/pty (since Linux 2.6.4)
              This directory contains two files relating to the number of UNIX
              98 pseudoterminals (see pts(4)) on the system.

       /proc/sys/kernel/pty/max
              This file defines the maximum number of pseudoterminals.

       /proc/sys/kernel/pty/nr
              This read-only  file  indicates  how  many  pseudoterminals  are
              currently in use.

       /proc/sys/kernel/random
              This  directory  contains  various  parameters  controlling  the
              operation of the file /dev/random.  See  random(4)  for  further
              information.

       /proc/sys/kernel/real-root-dev
              This   file   is   documented   in   the   kernel   source  file
              Documentation/initrd.txt.

       /proc/sys/kernel/reboot-cmd (Sparc only)
              This file seems to be a way to give an  argument  to  the  SPARC
              ROM/Flash  boot  loader.   Maybe  to  tell  it  what to do after
              rebooting?

       /proc/sys/kernel/rtsig-max
              (Only in kernels up to and including  2.6.7;  see  setrlimit(2))
              This  file can be used to tune the maximum number of POSIX real-
              time (queued) signals that can be outstanding in the system.

       /proc/sys/kernel/rtsig-nr
              (Only in kernels up to and including 2.6.7.)   This  file  shows
              the number POSIX real-time signals currently queued.

       /proc/sys/kernel/sem (since Linux 2.4)
              This  file  contains  4 numbers defining limits for System V IPC
              semaphores.  These fields are, in order:

              SEMMSL  The maximum semaphores per semaphore set.

              SEMMNS  A system-wide limit on the number of semaphores  in  all
                      semaphore sets.

              SEMOPM  The  maximum  number of operations that may be specified
                      in a semop(2) call.

              SEMMNI  A system-wide limit on the maximum number  of  semaphore
                      identifiers.

       /proc/sys/kernel/sg-big-buff
              This file shows the size of the generic SCSI device (sg) buffer.
              You can't tune it just yet, but you could change it  at  compile
              time  by  editing  include/scsi/sg.h  and  changing the value of
              SG_BIG_BUFF.  However, there shouldn't be any reason  to  change
              this value.

       /proc/sys/kernel/shmall
              This  file contains the system-wide limit on the total number of
              pages of System V shared memory.

       /proc/sys/kernel/shmmax
              This file can be used to query and set the run-time limit on the
              maximum  (System  V  IPC) shared memory segment size that can be
              created.  Shared memory segments up to 1GB are now supported  in
              the kernel.  This value defaults to SHMMAX.

       /proc/sys/kernel/shmmni
              (available  in  Linux  2.4  and  onward) This file specifies the
              system-wide maximum number of System V  shared  memory  segments
              that can be created.

       /proc/sys/kernel/sysrq
              This  file  controls  the functions allowed to be invoked by the
              SysRq key.  By default, the file contains 1 meaning  that  every
              possible  SysRq  request  is  allowed (in older kernel versions,
              SysRq  was  disabled  by  default,  and  you  were  required  to
              specifically enable it at run-time, but this is not the case any
              more).  Possible values in this file are:

                 0 - disable sysrq completely
                 1 - enable all functions of sysrq
                >1 - bitmask of allowed sysrq functions, as follows:
                        2 - enable control of console logging level
                        4 - enable control of keyboard (SAK, unraw)
                        8 - enable debugging dumps of processes etc.
                       16 - enable sync command
                       32 - enable remount read-only
                       64 - enable signalling of processes (term,  kill,  oom-
              kill)
                      128 - allow reboot/poweroff
                      256 - allow nicing of all real-time tasks

              This  file  is  only  present  if  the CONFIG_MAGIC_SYSRQ kernel
              configuration option is enabled.  For further  details  see  the
              kernel source file Documentation/sysrq.txt.

       /proc/sys/kernel/version
              This file contains a string like:

                  #5 Wed Feb 25 21:49:24 MET 1998

              The  "#5"  means  that  this is the fifth kernel built from this
              source base and the date behind it indicates the time the kernel
              was built.

       /proc/sys/kernel/threads-max (since Linux 2.3.11)
              This  file  specifies  the  system-wide  limit  on the number of
              threads (tasks) that can be created on the system.

       /proc/sys/kernel/zero-paged (PowerPC only)
              This file contains a flag.  When  enabled  (nonzero),  Linux-PPC
              will  pre-zero  pages  in  the  idle  loop, possibly speeding up
              get_free_pages.

       /proc/sys/net
              This directory contains networking stuff.  Explanations for some
              of  the  files  under  this directory can be found in tcp(7) and
              ip(7).

       /proc/sys/net/core/somaxconn
              This file defines a ceiling value for the  backlog  argument  of
              listen(2); see the listen(2) manual page for details.

       /proc/sys/proc
              This directory may be empty.

       /proc/sys/sunrpc
              This  directory  supports  Sun remote procedure call for network
              file system (NFS).  On some systems, it is not present.

       /proc/sys/vm
              This directory contains  files  for  memory  management  tuning,
              buffer and cache management.

       /proc/sys/vm/drop_caches (since Linux 2.6.16)
              Writing  to  this  file  causes the kernel to drop clean caches,
              dentries and inodes from memory, causing that memory  to  become
              free.

              To  free  pagecache,  use  echo 1 > /proc/sys/vm/drop_caches; to
              free dentries and inodes, use echo 2 > /proc/sys/vm/drop_caches;
              to   free   pagecache,   dentries  and  inodes,  use  echo  3  >
              /proc/sys/vm/drop_caches.

              Because this is a nondestructive operation and dirty objects are
              not freeable, the user should run sync(8) first.

       /proc/sys/vm/legacy_va_layout (since Linux 2.6.9)
              If  nonzero, this disables the new 32-bit memory-mapping layout;
              the kernel will use the legacy (2.4) layout for all processes.

       /proc/sys/vm/memory_failure_early_kill (since Linux 2.6.32)
              Control how to kill processes when an uncorrected  memory  error
              (typically  a  2-bit  error  in  a memory module) that cannot be
              handled by the kernel is detected in the background by hardware.
              In some cases (like the page still having a valid copy on disk),
              the  kernel  will  handle  the  failure  transparently   without
              affecting any applications.  But if there is no other up-to-date
              copy of the data, it will kill processes  to  prevent  any  data
              corruptions from propagating.

              The file has one of the following values:

              1:  Kill   all   processes   that  have  the  corrupted-and-not-
                  reloadable  page  mapped  as  soon  as  the  corruption   is
                  detected.   Note  this  is  not supported for a few types of
                  pages, like kernel internally allocated  data  or  the  swap
                  cache, but works for the majority of user pages.

              0:  Only  unmap  the  corrupted page from all processes and only
                  kill a process who tries to access it.

              The kill is performed using a SIGBUS signal with si_code set  to
              BUS_MCEERR_AO.   Processes  can handle this if they want to; see
              sigaction(2) for more details.

              This feature is  only  active  on  architectures/platforms  with
              advanced  machine  check  handling  and  depends on the hardware
              capabilities.

              Applications can override the memory_failure_early_kill  setting
              individually with the prctl(2) PR_MCE_KILL operation.

              Only    present    if    the    kernel   was   configured   with
              CONFIG_MEMORY_FAILURE.

       /proc/sys/vm/memory_failure_recovery (since Linux 2.6.32)
              Enable memory failure recovery (when supported by the platform)

              1:  Attempt recovery.

              0:  Always panic on a memory failure.

              Only   present   if   the    kernel    was    configured    with
              CONFIG_MEMORY_FAILURE.

       /proc/sys/vm/oom_dump_tasks (since Linux 2.6.25)
              Enables a system-wide task dump (excluding kernel threads) to be
              produced when the kernel  performs  an  OOM-killing.   The  dump
              includes  the  following  information  for  each  task  (thread,
              process): thread ID, real user ID, thread group ID (process ID),
              virtual memory size, resident set size, the CPU that the task is
              scheduled  on,   oom_adj   score   (see   the   description   of
              /proc/[pid]/oom_adj),  and  command  name.   This  is helpful to
              determine why the OOM-killer was invoked  and  to  identify  the
              rogue task that caused it.

              If this contains the value zero, this information is suppressed.
              On very large systems with thousands of tasks,  it  may  not  be
              feasible  to  dump  the  memory  state information for each one.
              Such systems should not be forced to incur a performance penalty
              in OOM situations when the information may not be desired.

              If  this  is  set to nonzero, this information is shown whenever
              the OOM-killer actually kills a memory-hogging task.

              The default value is 0.

       /proc/sys/vm/oom_kill_allocating_task (since Linux 2.6.24)
              This enables or disables killing the OOM-triggering task in out-
              of-memory situations.

              If  this  is  set  to zero, the OOM-killer will scan through the
              entire tasklist and select a task based on heuristics  to  kill.
              This  normally selects a rogue memory-hogging task that frees up
              a large amount of memory when killed.

              If this is set to nonzero, the OOM-killer simply kills the  task
              that  triggered  the  out-of-memory  condition.   This  avoids a
              possibly expensive tasklist scan.

              If /proc/sys/vm/panic_on_oom is  nonzero,  it  takes  precedence
              over        whatever        value        is        used       in
              /proc/sys/vm/oom_kill_allocating_task.

              The default value is 0.

       /proc/sys/vm/overcommit_memory
              This file contains the kernel virtual  memory  accounting  mode.
              Values are:

                     0: heuristic overcommit (this is the default)
                     1: always overcommit, never check
                     2: always check, never overcommit

              In  mode 0, calls of mmap(2) with MAP_NORESERVE are not checked,
              and the default check is very  weak,  leading  to  the  risk  of
              getting  a  process  "OOM-killed".   Under Linux 2.4 any nonzero
              value implies mode 1.  In mode 2 (available  since  Linux  2.6),
              the  total virtual address space on the system is limited to (SS
              + RAM*(r/100)), where SS is the size of the swap space, and  RAM
              is the size of the physical memory, and r is the contents of the
              file /proc/sys/vm/overcommit_ratio.

       /proc/sys/vm/overcommit_ratio
              See the description of /proc/sys/vm/overcommit_memory.

       /proc/sys/vm/panic_on_oom (since Linux 2.6.18)
              This enables or disables a  kernel  panic  in  an  out-of-memory
              situation.

              If this file is set to the value 0, the kernel's OOM-killer will
              kill some rogue process.  Usually, the  OOM-killer  is  able  to
              kill a rogue process and the system will survive.

              If  this  file  is  set to the value 1, then the kernel normally
              panics when out-of-memory happens.  However, if a process limits
              allocations  to  certain  nodes  using memory policies (mbind(2)
              MPOL_BIND) or cpusets (cpuset(7)) and those nodes  reach  memory
              exhaustion  status, one process may be killed by the OOM-killer.
              No panic occurs in this case: because other nodes' memory may be
              free,  this  means the system as a whole may not have reached an
              out-of-memory situation yet.

              If this file is set to the value 2,  the  kernel  always  panics
              when an out-of-memory condition occurs.

              The default value is 0.  1 and 2 are for failover of clustering.
              Select either according to your policy of failover.

       /proc/sys/vm/swappiness
              The value in this file controls how aggressively the kernel will
              swap memory pages.  Higher values increase aggressiveness, lower
              values decrease aggressiveness.  The default value is 60.

       /proc/sysrq-trigger (since Linux 2.4.21)
              Writing a  character  to  this  file  triggers  the  same  SysRq
              function as typing ALT-SysRq-<character> (see the description of
              /proc/sys/kernel/sysrq).  This file is normally only writable by
              root.    For   further   details  see  the  kernel  source  file
              Documentation/sysrq.txt.

       /proc/sysvipc
              Subdirectory containing  the  pseudo-files  msg,  sem  and  shm.
              These  files  list the System V Interprocess Communication (IPC)
              objects (respectively: message queues,  semaphores,  and  shared
              memory)  that  currently  exist on the system, providing similar
              information to that available via  ipcs(1).   These  files  have
              headers  and  are  formatted  (one IPC object per line) for easy
              understanding.  svipc(7)  provides  further  background  on  the
              information shown by these files.

       /proc/tty
              Subdirectory  containing the pseudo-files and subdirectories for
              tty drivers and line disciplines.

       /proc/uptime
              This file  contains  two  numbers:  the  uptime  of  the  system
              (seconds),  and  the  amount  of  time  spent  in  idle  process
              (seconds).

       /proc/version
              This string identifies the  kernel  version  that  is  currently
              running.   It  includes the contents of /proc/sys/kernel/ostype,
              /proc/sys/kernel/osrelease  and  /proc/sys/kernel/version.   For
              example:
            Linux version 1.0.9 (quinlan@phaze) #1 Sat May 14 01:51:54 EDT 1994

       /proc/vmstat (since Linux 2.6)
              This file displays various virtual memory statistics.

       /proc/zoneinfo (since Linux 2.6.13)
              This  file  display  information  about  memory  zones.  This is
              useful for analyzing virtual memory behavior.

NOTES

       Many strings (i.e., the  environment  and  command  line)  are  in  the
       internal format, with subfields terminated by null bytes ('\0'), so you
       may find that things are more readable if you use od -c  or  tr  "\000"
       "\n" to read them.  Alternatively, echo `cat <file>` works well.

       This manual page is incomplete, possibly inaccurate, and is the kind of
       thing that needs to be updated very often.

SEE ALSO

       cat(1), dmesg(1), find(1), free(1), ps(1), tr(1), uptime(1), chroot(2),
       mmap(2), readlink(2), syslog(2), slabinfo(5), hier(7), time(7), arp(8),
       hdparm(8),  ifconfig(8),   init(8),   lsmod(8),   lspci(8),   mount(8),
       netstat(8), procinfo(8), route(8)
       The    kernel    source    files:   Documentation/filesystems/proc.txt,
       Documentation/sysctl/vm.txt

COLOPHON

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       description  of  the project, and information about reporting bugs, can
       be found at http://man7.org/linux/man-pages/.