Provided by: sg3-utils_1.46-1build1_amd64 bug


       sg3_utils - a package of utilities for sending SCSI commands


       sg_*  [--dry-run]  [--enumerate]  [--help]  [--hex]  [--in=FN] [--inhex=FN] [--maxlen=LEN]
       [--raw] [--timeout=SECS] [--verbose] [--version] [OTHER_OPTIONS] DEVICE


       sg3_utils is a package of utilities that send SCSI commands to the given DEVICE via a SCSI
       pass through interface provided by the host operating system.

       The names of all utilities start with "sg" and most start with "sg_" often followed by the
       name, or a shortening of the name, of the SCSI command that they  send.  For  example  the
       "sg_verify" utility sends the SCSI VERIFY command. A mapping between SCSI commands and the
       sg3_utils utilities that issue them is shown in the COVERAGE file. The sg_raw utility  can
       be  used  to  send  an  arbitrary SCSI command (supplied on the command line) to the given

       sg_decode_sense can be used to decode SCSI sense data given on the command line  or  in  a
       file.  sg_raw  -vvv  will  output  the T10 name of a given SCSI CDB which is most often 16
       bytes or less in length.

       SCSI draft standards can be found at . The standards themselves can  be
       purchased  from  ANSI  and other standards organizations.  A good overview of various SCSI
       standards can be seen in with the SCSI command sets  in  the
       upper  part  of  the  diagram. The highest level (i.e. most abstract) document is the SCSI
       Architecture Model (SAM) with SAM-5 being the most recent standard (ANSI INCITS  515-2016)
       with  the  most  recent  draft  being  SAM-6 revision 4 . SCSI commands in common with all
       device types can be found in SCSI Primary Commands (SPC) of which SPC-4 is the most recent
       standard  (ANSI  INCITS  513-2015).  The most recent SPC draft is SPC-5 revision 21. Block
       device specific commands (e.g. as used by disks) are in SBC, those for tape drives in SSC,
       those for SCSI enclosures in SES and those for CD/DVD/BD drives in MMC.

       It  is becoming more common to control ATA disks with the SCSI command set.  This involves
       the translation of SCSI commands to their corresponding ATA equivalents (and  that  is  an
       imperfect  mapping in some cases). The relevant standard is called SCSI to ATA Translation
       (SAT, SAT-2 and SAT-3) are now standards at INCITS(ANSI) and ISO while  SAT-4  is  at  the
       draft  stage.  The logic to perform the command translation is often called a SAT Layer or
       SATL and may be within an operating system, in host bus adapter firmware or in an external
       device (e.g. associated with a SAS expander). See for more information.

       There  is some support for SCSI tape devices but not for their basic operation. The reader
       is referred to the "mt" utility.

       There are two generations of command line option usage. The newer utilities (written since
       July  2004)  use  the  getopt_long()  function  to  parse  command line options. With that
       function, each option has two representations: a short form (e.g. '-v') and a longer  form
       (e.g. '--verbose'). If an argument is required then it follows a space (optionally) in the
       short form and a "=" in the longer form (e.g. in  the  sg_verify  utility  '-l  2a6h'  and
       '--lba=2a6h'  are  equivalent).  Note  that  with getopt_long(), short form options can be
       elided, for example: '-all' is equivalent to '-a -l -l'.  The DEVICE argument  may  appear
       after, between or prior to any options.

       The  older  utilities,  including  as  sg_inq,  sg_logs,  sg_modes,  sg_opcode,  sg_rbuff,
       sg_readcap, sg_senddiag, sg_start and sg_turs had individual command line processing  code
       typically  based  on  a  single  "-" followed by one or more characters. If an argument is
       needed then it follows a "=" ( e.g. '-p=1f' in sg_modes with its older interface). Various
       options  can  be  elided  as  long  as  it  is  not  ambiguous (e.g. '-vv' to increase the

       Over time the command line interface of these older utilities became messy and  overloaded
       with  options.  So  in  sg3_utils  version  1.23 the command line interface of these older
       utilities was altered to have both a  cleaner  getopt_long()  interface  and  their  older
       interface  for  backward  compatibility.   By  default  these  older  utilities  use their
       getopt_long() based interface.  The getopt_long() is a GNU extension (i.e. not  yet  POSIX
       certified)  but  more recent command line utilities tend to use it. That can be overridden
       by defining the SG3_UTILS_OLD_OPTS environment variable or using '-O' or  '--old'  as  the
       first command line option. The man pages of the older utilities documents the details.

       Several  sg3_utils  utilities  are  based  on  the Unix dd command (e.g. sg_dd) and permit
       copying data at the level of SCSI READ and WRITE commands. sg_dd is tightly bound to Linux
       and  hence is not ported to other OSes. A more generic utility (than sg_dd) called ddpt in
       a package of the same name has been ported to other OSes.


       The SG3_UTILS_OLD_OPTS environment variable is explained in the previous  section.  It  is
       only for backward compatibility of the command line options for older utilities.

       The  SG3_UTILS_DSENSE  environment variable may be set to a number. It is only used by the
       embedded SNTL within the library used by the utilities in this library. SNTL is a SCSI  to
       NVMe  Translation  Layer.  This  environment variable defaults to 0 which will lead to any
       utility that issues a SCSI command that is translated to a NVMe command (by  the  embedded
       SNTL)  that  fails  at  the  NVMe  dvice,  to return SCSI sense in 'fixed' format. If this
       variable is non-zero then then the returned SCSI sense will be in 'descriptor' format.

       Several utilities have their  own  environment  variable  setting  (e.g.   sg_persist  has
       SG_PERSIST_IN_RDONLY). See individual utility man pages for more information.

       There is a Linux specific environment variable called SG3_UTILS_LINUX_NANO that if defined
       and the sg driver in the system is  4.0.30  or  later,  will  show  command  durations  in
       nanoseconds  rather  than  the default milliseconds.  Command durations are typically only
       shown if --verbose is used 3 or more times. Due to an interface problem (a 32 bit  integer
       that  should  be  64  bits with the benefit of hindsight) the maximum duration that can be
       represented in nanoseconds is about 4.2 seconds. If longer durations may occur then  don't
       define this environment variable (or undefine it).


       Most  disk block devices have names like /dev/sda, /dev/sdb, /dev/sdc, etc.  SCSI disks in
       Linux have always had names like that but in recent  Linux  kernels  it  has  become  more
       common  for  many  other  disks (including SATA disks and USB storage devices) to be named
       like that. Partitions within a disk are specified by a number appended to the device name,
       starting at 1 (e.g. /dev/sda1 ).

       Tape  drives  are  named  /dev/st<num>  or  /dev/nst<num>  where  <num>  starts  at  zero.
       Additionally one letter from this list: "lma" may be appended to the name. CD, DVD and  BD
       readers  (and  writers)  are  named /dev/sr<num> where <num> start at zero. There are less
       used SCSI device type names, the dmesg and the lsscsi commands may help to find if any are
       attached to a running system.

       There  is also a SCSI device driver which offers alternate generic access to SCSI devices.
       It uses names of the form /dev/sg<num> where <num> starts at zero. The "lsscsi -g" command
       may  be  useful  in finding these and which generic name corresponds to a device type name
       (e.g. /dev/sg2 may correspond to /dev/sda). In the lk 2.6  series  a  block  SCSI  generic
       driver was introduced and its names are of the form /dev/bsg/<h:c:t:l> where h, c, t and l
       are numbers. Again see the lsscsi command to find the  correspondence  between  that  SCSI
       tuple (i.e. <h:c:t:l>) and alternate device names.

       Prior  to  the Linux kernel 2.6 series these utilities could only use generic device names
       (e.g. /dev/sg1 ). In almost all cases in the Linux kernel 2.6 series, any device name  can
       be used by these utilities.

       Very little has changed in Linux device naming in the Linux kernel 3 and 4 series.


       Storage  and  related devices can have several device names in Windows.  Probably the most
       common in the volume name (e.g. "D:"). There are also  a  "class"  device  names  such  as
       "PhysicalDrive<n>", "CDROM<n>" and "TAPE<n>". <n> is an integer starting at 0 allocated in
       ascending order as devices are discovered (and sometimes rediscovered).

       Some storage devices have a SCSI lower level device name which starts with a SCSI (pseudo)
       adapter  name  of  the  form  "SCSI<n>:". To this is added sub-addressing in the form of a
       "bus" number, a "target" identifier and a LUN (Logical Unit Number). The "bus"  number  is
       also  known  as  a  "PathId".   These  are  assembled  to  form a device name of the form:
       "SCSI<n>:<bus>,<target>,<lun>". The trailing ",<lun>" may be omitted in which case  a  LUN
       of  zero  is  assumed.  This  lower  level device name cannot often be used directly since
       Windows blocks attempts to use it if a class driver has "claimed" the  device.  There  are
       SCSI  device  types  (e.g.   Automation/Drive  interface type) for which there is no class
       driver. At least two transports ("bus types" in Windows jargon): USB and IEEE 1394 do  not
       have a "scsi" device names of this form.

       In  keeping  with  DOS  file  system conventions, the various device names can be given in
       upper, lower or mixed case. Since "PhysicalDrive<n>" is tedious to write, a shortened form
       of "PD<n>" is permitted by all utilities in this package.

       A  single  device (e.g. a disk) can have many device names. For example: "PD0" can also be
       "C:", "D:" and "SCSI0:0,1,0".  The  two  volume  names  reflect  that  the  disk  has  two
       partitions on it. Disk partitions that are not recognized by Windows are not usually given
       a volume name. However Vista does show a volume name for a disk which  has  no  partitions
       recognized  by  it  and  when  selected invites the user to format it (which may be rather
       unfriendly to other OSes).

       These utilities assume a given device name is in the Win32 device namespace.  To make that
       explicit  "\\.\"  can  be  prepended to the device names mentioned in this section. Beware
       that backslash is an escape character in Unix like shells and the C programming  language.
       In a shell like Msys (from MinGW) each backslash may need to be typed twice.

       The  sg_scan  utility within this package lists out Windows device names in a form that is
       suitable for other utilities in this package to use.


       SCSI disks have block names of the form /dev/da<num> where <num> is an integer starting at
       zero.  The  "da"  is  replaced  by  "sa"  for SCSI tape drives and "cd" for SCSI CD/DVD/BD
       drives. Each SCSI device  has  a  corresponding  pass-through  device  name  of  the  form
       /dev/pass<num>  where  <num>  is  an  integer  starting  at zero. The "camcontrol devlist"
       command may be useful for finding out which  SCSI  device  names  are  available  and  the
       correspondence between class and pass-through names.

       FreeBSD  allows device names to be given without the leading "/dev/" (e.g.  da0 instead of
       /dev/da0). That worked in this package up until version 1.43  when  the  unadorned  device
       name  (e.g.  "da0")  gave  an  error.  The original action (i.e. allowing unadorned device
       names) has been restored in version 1.46 . Also note that symlinks (to device  names)  are
       followed before prepending "/dev/" if the resultant name doesn't start with a "/".


       SCSI  device  names  below  the /dev directory have a form like: c5t4d3s2 where the number
       following "c" is the controller (HBA) number, the  number  following  "t"  is  the  target
       number  (from  the  SCSI parallel interface days) and the number following "d" is the LUN.
       Following the "s" is the slice number which is related to a partition  and  by  convention
       "s2" is the whole disk.

       OpenSolaris  also  has a c5t4d3p2 form where the number following the "p" is the partition
       number apart from "p0" which is the whole disk. So a whole disk  may  be  referred  to  as
       either c5t4d3, c5t4d3s2 or c5t4d3p0 .

       And  these  device  names  are  duplicated  in the /dev/dsk and /dev/rdsk directories. The
       former is the block device name and the latter is for "raw" (or char device) access  which
       is   what   sg3_utils   needs.   So   in   OpenSolaris   something  of  the  form  'sg_inq
       /dev/rdsk/c5t4d3p0' should work.  If it doesn't work then add a  '-vvv'  option  for  more
       debug  information.   Trying  this form 'sg_inq /dev/dsk/c5t4d3p0' (note "rdsk" changed to
       "dsk") will result in an "inappropriate ioctl for device" error.

       The device names within the /dev directory are typically symbolic  links  to  much  longer
       topological names in the /device directory. In Solaris cd/dvd/bd drives seem to be treated
       as disks and so are found in the /dev/rdsk directory. Tape drives appear in  the  /dev/rmt

       There is also a sgen (SCSI generic) driver which by default does not attach to any device.
       See the /kernel/drv/sgen.conf file to control what is attached. Any attached  device  will
       have a device name of the form /dev/scsi/c5t4d3 .

       Listing  available  SCSI  devices  in  Solaris  seems to be a challenge. "Use the 'format'
       command" advice works but seems a very dangerous way to  list  devices.  [It  does  prompt
       again  before  doing  any  damage.] 'devfsadm -Cv' cleans out the clutter in the /dev/rdsk
       directory, only leaving what is "live". The "cfgadm -v" command looks promising.


       NVMe (or NVM Express) is a relatively new storage transport and command set. The level  of
       abstraction of the NVMe command set is somewhat lower the SCSI command sets, closer to the
       level of abstraction of ATA (and SATA) command sets. NVMe claims to be designed with flash
       and  modern  "solid  state" storage in mind, something unheard of when SCSI was originally
       developed in the 1980s.

       The SCSI command sets' advantage is the length of time they have been  in  place  and  the
       existing  tools (like these) to support it. Plus SCSI command sets level of abstraction is
       both and advantage and disadvantage. Recently the NVME-MI (Management Interface) designers
       decide  to  use  the SCSI Enclosure Services (SES-3) standard "as is" with the addition of
       two tunnelling NVME-MI commands: SES Send  and  SES  Receive.  This  means  after  the  OS
       interface differences are taken into account, the sg_ses, sg_ses_microcode and sg_senddiag
       utilities can be used on a NVMe device that supports a newer version of NVME-MI.

       The NVME-MI SES Send and SES Receive commands correspond to the SCSI SEND  DIAGNOSTIC  and
       RECEIVE  DIAGNOSTIC RESULTS commands respectively.  There are however a few other commands
       that need to be translated, the most important of which is the SCSI INQUIRY command to the
       NVMe  Identify  controller/namespace.  Starting  in version 1.43 these utilities contain a
       small SNTL (SCSI to NVMe Translation Layer) to take care of these details.

       As a side effect of this "juggling" if the sg_inq utility is  used  (without  the  --page=
       option)  on  a  NVMe  DEVICE  then  the  actual  NVMe  Identifier (controller and possibly
       namespace) responses are decoded and output. However if 'sg_inq --page=sinq  <device>'  is
       given  for  the  same  DEVICE  then  parts  of  the NVMe Identify controller and namespace
       response are translated to a SCSI standard INQUIRY response  which  is  then  decoded  and

       Apart  from  the  special  case with the sg_inq, all other utilities in the package assume
       they are talking to a SCSI device and decode any response accordingly. One  easy  way  for
       users  to  see  the  underlying  device  is a NVMe device is the standard INQUIRY response
       Vendor Identification field of "NVMe    " (an 8 character long string with 4 spaces to the

       The  following  SCSI  commands  are currently supported by the SNTL library: INQUIRY, MODE
       UNIT READY, VERIFY(10,16), WRITE(10,16) and WRITE SAME(10,16).


       To  aid  scripts that call these utilities, the exit status is set to indicate success (0)
       or failure (1 or more). Note that some of the lower values correspond to  the  SCSI  sense
       key values.

       The  exit status values listed below can be given to the sg_decode_sense utility (which is
       found in this package) as follows:
         sg_decode_sense --err=<exit_status>
       and a short explanatory string will be output to stdout.

       The exit status values are:

       0      success. Also used for some utilities that wish to return a boolean value  for  the
              "true"  case  (and  that no error has occurred). The false case is conveyed by exit
              status 36.

       1      syntax error. Either illegal command line options, options with bad arguments or  a
              combination of options that is not permitted.

       2      the  DEVICE  reports  that it is not ready for the operation requested.  The DEVICE
              may be in the process of becoming ready (e.g.  spinning up but not at speed) so the
              utility may work after a wait. In Linux the DEVICE may be temporarily blocked while
              error recovery is taking place.

       3      the DEVICE reports a medium or hardware error (or a blank check).  For  example  an
              attempt to read a corrupted block on a disk will yield this value.

       5      the  DEVICE  reports  an "illegal request" with an additional sense code other than
              "invalid command operation code". This is often a supported command  with  a  field
              set  requesting  an  unsupported  capability.  For commands that require a "service
              action" field this value can indicate that the command  with  that  service  action
              value is not supported.

       6      the  DEVICE  reports  a  "unit  attention"  condition.  This usually indicates that
              something unrelated to the requested command has occurred  (e.g.  a  device  reset)
              potentially before the current SCSI command was sent. The requested command has not
              been executed by the device. Note that unit attention conditions are  usually  only
              reported once by a device.

       7      the  DEVICE  reports  a  "data  protect" sense key. This implies some mechanism has
              blocked writes (or possibly all access to the media).

       9      the DEVICE reports an illegal request with an additional  sense  code  of  "invalid
              command operation code" which means that it doesn't support the requested command.

       10     the DEVICE reports a "copy aborted". This implies another command or device problem
              has stopped a copy operation. The EXTENDED COPY family of commands (including WRITE
              USING TOKEN) may return this sense key.

       11     the  DEVICE  reports  an  aborted  command.  In  some cases aborted commands can be
              retried immediately (e.g. if the transport aborted the command due to congestion).

       14     the DEVICE reports a miscompare sense key. VERIFY and COMPARE  AND  WRITE  commands
              may report this.

       15     the  utility  is  unable to open, close or use the given DEVICE or some other file.
              The given file name could be incorrect or there may be permission problems.  Adding
              the '-v' option may give more information.

       17     a  SCSI "Illegal request" sense code received with a flag indicating the Info field
              is valid. This is often a LBA but its meaning is command specific.

       18     the DEVICE reports a medium or hardware error  (or  a  blank  check)  with  a  flag
              indicating  the  Info field is valid. This is often a LBA (of the first encountered
              error) but its meaning is command specific.

       20     the DEVICE reports it has a check condition but "no sense" and non-zero information
              in  its  additional  sense  codes.  Some  polling commands (e.g. REQUEST SENSE) can
              receive this response. There may be useful information in the sense data such as  a
              progress indication.

       21     the  DEVICE reports a "recovered error". The requested command was successful. Most
              likely a utility will report a recovered error to  stderr  and  continue,  probably
              leaving the utility with an exit status of 0 .

       22     the DEVICE reports that the current command or its parameters imply a logical block
              address (LBA) that is out of range. This happens surprisingly often when trying  to
              access  the  last  block  on  a storage device; either a classic "off by one" logic
              error or a misreading of the response from READ CAPACITY(10 or  16)  in  which  the
              address  of  the  last  block  rather  than  the  number of blocks on the DEVICE is
              returned. Since LBAs are origin zero they range from 0 to n-1 where n is the number
              of  blocks  on  the DEVICE, so the LBA of the last block is one less than the total
              number of blocks.

       24     the DEVICE reports a SCSI status of "reservation conflict". This  means  access  to
              the  DEVICE  with the current command has been blocked because another machine (HBA
              or SCSI "initiator") holds a reservation on this DEVICE.  On  modern  SCSI  systems
              this is related to the use of the PERSISTENT RESERVATION family of commands.

       25     the  DEVICE  reports a SCSI status of "condition met". Currently only the PRE-FETCH
              command (see SBC-4) yields this status.

       26     the DEVICE reports a SCSI status of  "busy".  SAM-6  defines  this  status  as  the
              logical  unit  is  temporarily  unable  to  process a command. It is recommended to
              re-issue the command.

       27     the DEVICE reports a SCSI status of "task set full".

       28     the DEVICE reports  a  SCSI  status  of  "ACA  active".  ACA  is  "auto  contingent
              allegiance" and is seldom used.

       29     the  DEVICE reports a SCSI status of "task aborted". SAM-5 says: "This status shall
              be returned if a command is aborted by a command or  task  management  function  on
              another I_T nexus and the Control mode page TAS bit is set to one".

       31     error involving two or more command line options. They may be contradicting, select
              an unsupported mode, or a required option (given the context) is missing.

       32     there is a logic error in  the  utility.  It  corresponds  to  code  comments  like
              "shouldn't/can't get here". Perhaps the author should be informed.

       33     the command sent to DEVICE has timed out.

       34     this  is a Windows only exit status and indicates that the Windows error number (32
              bits) cannot meaningfully be mapped to an equivalent Unix error number returned  as
              the exit status (7 bits).

       36     no  error  has  occurred plus the utility wants to convey a boolean value of false.
              The corresponding true value is conveyed by a 0 exit status.

       40     the command sent to DEVICE has received an "aborted  command"  sense  key  with  an
              additional  sense  code  of 0x10. This value is related to problems with protection
              information (PI or DIF). For example this error may occur when reading a block on a
              drive that has never been written (or is unmapped) if that drive was formatted with
              type 1, 2 or 3 protection.

       41     the command sent to DEVICE has received an "aborted  command"  sense  key  with  an
              additional  sense code of 0x10 (as with error code) plus a flag indicating the Info
              field is valid.

       48     this is an internal message indicating a NVMe status field (SF) is other than  zero
              after  a  command has been executed (i.e. something went wrong).  Work in this area
              is currently experimental.

       49     low level driver reports a response's residual count (i.e. number of bytes actually
              received by HBA is 'requested_bytes - residual_count') that is nonsensical.

       50     OS  system  calls  that  fail  often return a small integer number to help. In Unix
              these are called "errno" values where 0 implies no error.  These  error  codes  set
              aside  51  to  96  for  mapping  these errno values but that may not be sufficient.
              Higher errno values that cannot be mapped are all mapped to this value (i.e. 50).
              Note that an errno value of 0 is mapped to error code 0.

       50 + <os_error_number>
              OS system calls that fail often return a small integer number to help indicate what
              the error is. For example in Unix the inability of a system call to allocate memory
              returns (in 'errno') ENOMEM which often is associated with the integer  12.  So  62
              (i.e.  '50  +  12')  may be returned by a utility in this case. It is also possible
              that a utility in this package reports 50+ENOMEM when it can't allocate memory, not
              necessarily  from  an  OS system call. In recent versions of Linux the file showing
              the mapping between symbolic constants (e.g. ENOMEM) and the corresponding  integer
              is in the kernel source code file: include/uapi/asm-generic/errno-base.h
              Note  that  errno  values  that are greater than or equal to 47 cannot fit in range
              provided. Instead they are all mapped to 50 as discussed in the previous entry.

       97     a SCSI command response failed sanity checks.

       98     the DEVICE reports it has a check condition but the error doesn't fit into  any  of
              the above categories.

       99     any errors that can't be categorized into values 1 to 98 may yield this value. This
              includes transport and operating system errors after the command has been  sent  to
              the device.

              these  error  codes  are used by the ddpt utility which uses the sg3_utils library.
              They are mainly specialized error codes associated with offloaded copies.

       126    the utility was found but could not be executed. That might occur if the executable
              does not have execute permissions.

       127    This is the exit status for utility not found. That might occur when a script calls
              a utility in this package but the PATH environment variable has not  been  properly
              set up, so the script cannot find the executable.

       128 + <signum>
              If a signal kills a utility then the exit status is 128 plus the signal number. For
              example if a segmentation fault occurs  then  a  utility  is  typically  killed  by
              SIGSEGV which according to 'man 7 signal' has an associated signal number of 11; so
              the exit status will be 139 .

       255    the utility tried to yield an exit status of 255 or larger. That should not happen;
              given here for completeness.

       Most  of the error conditions reported above will be repeatable (an example of one that is
       not is "unit attention") so the utility can be run again with the '-v' option (or several)
       to obtain more information.


       Arguments  to  long  options are mandatory for short options as well. In the short form an
       argument to an option uses zero or more spaces as a separator (i.e. the  short  form  does
       not use "=" as a separator).

       If  an  option takes a numeric argument then that argument is assumed to be decimal unless
       otherwise indicated (e.g. with a leading "0x", a trailing "h" or as  noted  in  the  usage

       Some  options  are  used uniformly in most of the utilities in this package. Those options
       are listed below. Note that there are some exceptions.

       -d, --dry-run
              utilities that can cause lots of user data to be lost or overwritten sometimes have
              a --dry-run option. Device modifying actions are typically bypassed (or skipped) to
              implement a policy of "do no harm".  This allows complex command  line  invocations
              to  be  tested  before  the  action required (e.g. format a disk) is performed. The
              --dry-run option has become a common feature of many command line  utilities  (e.g.
              the Unix 'patch' command), not just those from this package.
              Note  that  most  hyphenated option names in this package also can be given with an
              underscore rather than a hyphen (e.g.  --dry_run).

       -e, --enumerate
              some utilities (e.g. sg_ses and sg_vpd) store a  lot  of  information  in  internal
              tables. This option will output that information in some readable form (e.g. sorted
              by an acronym or by page number) then exit. Note that with this  option  DEVICE  is
              ignored (as are most other options) and no SCSI IO takes place, so the invoker does
              not need any elevated permissions.

       -h, -?, --help
              output the usage message then exit. In  a  few  older  utilities  the  '-h'  option
              requests  hexadecimal  output. In these cases the '-?' option will output the usage
              message then exit.

       -H, --hex
              for SCSI commands that yield a non-trivial response, print  out  that  response  in
              ASCII  hexadecimal.  To  produce  hexadecimal that can be parsed by other utilities
              (e.g. without a relative address to the left and without trailing ASCII)  use  this
              option three or four times.

       -i, --in=FN
              many  SCSI  commands  fetch  a  significant amount of data (returned in the data-in
              buffer) which several of these utilities  decode  (e.g.  sg_vpd  and  sg_logs).  To
              separate  the  two  steps of fetching the data from a SCSI device and then decoding
              it, this option has been added. The first step (fetching  the  data)  can  be  done
              using  the  --hex or --raw option and redirecting the command line output to a file
              (often done with ">" in Unix based operating systems). The difference between --hex
              and  --raw  is  that  the  former  produces output in ASCII hexadecimal while --raw
              produces its output in "raw" binary.
              The second step (i.e. decoding the SCSI response data now held in a  file)  can  be
              done  using  this  --in=FN  option where the file name is FN. If "-" is used for FN
              then stdin is assumed, again this allows for command line redirection (or  piping).
              That  file  (or  stdin)  is  assumed  to contain ASCII hexadecimal unless the --raw
              option is also given in which case it is assumed to  be  binary.  Notice  that  the
              meaning  of  the  --raw  option  is  "flipped" when used with --in=FN to act on the
              input, typically it acts on the output data.
              Since the structure of the data returned by SCSI commands varies considerably  then
              the  usage  information or the manpage of the utility being used should be checked.
              In some cases --hex may need to be used multiple times (and  is  more  conveniently
              given as '-HH' or '-HHH).

       -i, --inhex=FN
              This  option  has the same or similar functionality as --in=FN. And perhaps 'inhex'
              is more descriptive since by default, ASCII hexadecimal is expected in the contents
              of  file:  FN. Alternatively the short form option may be -I or -X. See the "FORMAT
              OF FILES CONTAINING ASCII HEX" section below for more information.

       -m, --maxlen=LEN
              several important SCSI commands (e.g. INQUIRY and MODE SENSE) have response lengths
              that  vary  depending on many factors, only some of which these utilities take into
              account. The maximum response length is  typically  specified  in  the  'allocation
              length'  field  of  the cdb. In the absence of this option, several utilities use a
              default allocation length (sometimes recommended in the SCSI draft standards) or  a
              "double  fetch"  strategy.   See sg_logs(8) for its description of a "double fetch"
              strategy. These techniques are imperfect and in the presence of faulty SCSI targets
              can  cause  problems  (e.g. some USB mass storage devices freeze if they receive an
              INQUIRY allocation length other than 36). Also use  of  this  option  disables  any
              "double fetch" strategy that may have otherwise been used.

       -r, --raw
              for SCSI commands that yield a non-trivial response, output that response in binary
              to stdout. If any error messages or warning are produced they are usually  sent  to
              stderr so as to not interfere with the output from this option.
              Some utilities that consume data to send to the DEVICE along with the SCSI command,
              use this option. Alternatively the --in=FN option causes DEVICE to be  ignored  and
              the response data (to be decoded) fetched from a file named FN. In these cases this
              option may indicate that binary data can be read from stdin  or  from  a  nominated
              file (e.g. FN).

       -t, --timeout=SECS
              utilities   that   issue  potentially  long-running  SCSI  commands  often  have  a
              --timeout=SECS option. This typically instructs the operating system to  abort  the
              SCSI  command  in  question  once  the  timeout  expires. Aborting SCSI commands is
              typically a messy business and in the case of format like commands  may  leave  the
              device in a "format corrupt" state requiring another long-running re-initialization
              command to be sent. The argument, SECS, is usually in seconds and the short form of
              the  option  may  be something other than -t since the timeout option was typically
              added later as storage devices  grew  in  size  and  initialization  commands  took
              longer.  Since  many utilities had relatively long internal command timeouts before
              this option was introduced, the actual  command  timeout  given  to  the  operating
              systems is the higher of the internal timeout and SECS.
              Many  long  running  SCSI  commands  have  an IMMED bit which causes the command to
              finish relatively quickly but the initialization process to continue. In such cases
              the  REQUEST  SENSE  command  can  be  used  to  monitor progress with its progress
              indication field (see the sg_requests and sg_turs utilities).  Utilities that  send
              such  SCSI  command  either  have an --immed option or a --wait option which is the
              logical inverse of the "immediate" action.

       -v, --verbose
              increase the level of verbosity, (i.e. debug output). Can be used multiple times to
              further  increase  verbosity. The additional output caused by this option is almost
              always sent to stderr.

       -V, --version
              print the version string and then exit. Each utility has its own version number and
              date of last code change.


       Many  utilities  have  command  line  options  that  take numeric arguments. These numeric
       arguments can be large values (e.g. a logical block address (LBA) on a disk)  and  can  be
       inconvenient   to   enter   in  the  default  decimal  representation.  So  various  other
       representations are permitted.

       Multiplicative suffixes are accepted. They are one, two or three letter  strings  appended
       directly after the number to which they apply:

          c C         *1
          w W         *2
          b B         *512
          k K KiB     *1024
          KB kB       *1000
          m M MiB     *1048576
          MB mB       *1000000
          g G GiB     *(2^30)
          GB gB       *(10^9)
          t T TiB     *(2^40)
          TB          *(10^12)
          p P PiB     *(2^50)
          PB          *(10^15)

       An  example  is  "2k"  for  2048.  The large tera and peta suffixes are only available for
       numeric arguments that might require 64 bits to represent internally.

       These multiplicative suffixes are compatible with GNU's  dd  command  (since  2002)  which
       claims compliance with SI and with IEC 60027-2.

       A  suffix  of the form "x<n>" multiplies the preceding number by <n>. An example is "2x33"
       for "66". The left argument cannot be '0' as  '0x'  will  be  interpreted  as  hexadecimal
       number  prefix  (see  below).  The  left  argument  to  the  multiplication  must end in a
       hexadecimal digit (i.e.  0 to f)  and  the  whole  expression  cannot  have  any  embedded
       whitespace (e.g.  spaces). An ugly example: "0xfx0x2" for 30.

       A  suffix  of  the  form "+<n>" adds the preceding number to <n>. An example is "3+1k" for
       "1027". The left argument to the addition must end in a hexadecimal digit (i.e.  0  to  f)
       and  the  whole  expression  cannot  have  any  embedded whitespace (e.g. spaces). Another
       example: "0xf+0x2" for 17.

       Alternatively numerical arguments can be given in hexadecimal. There are two syntaxes. The
       number  can be preceded by either "0x" or "0X" as found in the C programming language. The
       second hexadecimal representation  is  a  trailing  "h"  or  "H"  as  found  in  (storage)
       standards. When hex numbers are given, multipliers cannot be used. For example the decimal
       value "256" can be given as "0x100" or "100h".


       Such a file is assumed to contain a sequence of one or two digit ASCII hexadecimal  values
       separated  by whitespace. "Whitespace consists of either spaces, tabs, blank lines, or any
       combination thereof". Each one or two digit ASCII hex pair is decoded into a byte (i.e.  8
       bits).  The  following  will be decoded to valid (ascending valued) bytes: '0', '01', '3',
       'c', 'F', '4a', 'cC', 'ff'.  Lines containing only whitespace are ignored. The contents of
       any  line  containing  a  hash mark ('#') is ignored from that point until the end of that
       line. Users are encouraged to use hash marks to  introduce  comments  in  hex  files.  The
       author  uses  the  extension'.hex'  on  such  files.  Examples can be found in the 'inhex'


       There are two standardized methods for downloading microcode (i.e. device firmware)  to  a
       SCSI  device.  The  more  general  way  is  with  the  SCSI  WRITE BUFFER command, see the
       sg_write_buffer utility. SCSI enclosures have their  own  method  based  on  the  Download
       microcode control/status diagnostic page, see the sg_ses_microcode utility.


       There  are  several  bash shell scripts in the 'scripts' subdirectory that invoke compiled
       utilities (e.g. sg_readcap). Several of the scripts start with 'scsi_' rather than  'sg_'.
       One  purpose  of  these  scripts is to call the same utility (e.g. sg_readcap) on multiple
       devices. Most of the basic compiled utilities only allow one device as an  argument.  Some
       distributions  install  these scripts in a more visible directory (e.g. /usr/bin). Some of
       these scripts have man page entries. See the README file in the 'scripts' subdirectory.

       There is some example C code plus  examples  of  complex  invocations  in  the  'examples'
       subdirectory.  There  is also a README file. The example C may be a simpler example of how
       to use a SCSI  pass-through  in  Linux  than  the  main  utilities  (found  in  the  'src'
       subdirectory).  This  is  due  to  the fewer abstraction layers (e.g. they don't worry the
       MinGW in Windows may open a file in text rather than binary mode).

       Some utilities that  the  author  has  found  useful  have  been  placed  in  the  'utils'


       There  is a web page discussing this package at . The
       device naming used  by  this  package  on  various  operating  systems  is  discussed  at:    .    There    is    a   git   code   mirror   at . The principle code repository uses subversion and
       is  on  the author's equipment. The author keeps track of this via the subversion revision
       number which is an ascending integer (currently at  774  for  this  package).  The  github
       mirror  gets  updated  periodically from the author's repository. Depending on the time of
       update, the above Downloads section at may be more up to date than the  github


       Written by Douglas Gilbert. Some utilities have been contributed, see the CREDITS file and
       individual source files (in the 'src' directory).


       Report bugs to <dgilbert at interlog dot com>.


       Copyright © 1999-2021 Douglas Gilbert
       Some utilities are distributed under a GPL version 2 license while  others,  usually  more
       recent  ones,  are  under  a  FreeBSD  license.  The  files  that are common to almost all
       utilities and thus contain the most reusable code, namely sg_lib.[hc],  sg_cmds_basic.[hc]
       and  sg_cmds_extra.[hc]  are  under  a FreeBSD license. There is NO warranty; not even for


       sdparm(sdparm), ddpt(ddpt), lsscsi(lsscsi), dmesg(1), mt(1)