NAME

       since - display content of a file since the last time

SYNOPSIS

       since [-aefhlmnqvxz] [-d seconds] [-s file] files

DESCRIPTION

       since  is a utility designed to monitor log files.  since is similar to tail(2) as it also
       displays information appended to a file.  However since only displays the data  which  has
       been added since the last time since was run. If since is run on a particular file for the
       first time, then the entire file is displayed.

EXAMPLE

       since /var/log/apache/{access,error}_log > /dev/null
       lynx --dump http://localhost/ > /dev/null
       since /var/log/apache/{access,error}_log

OPTIONS

       -a     Make updates to the since state files atomic. This option configures since to use a
              temporary file and a rename(2) instead of updating the state file in situ.

       -d seconds
              Specify  the  number  of integer seconds to wait between polling files for changes.
              This option is only relevant in conjunction with the -f option and if  the  inotify
              mechanism is not being used.

       -e     Print the header lines to standard error instead of standard output.

       -f     Follow  the  specified  files. This option is analogous to tail -f as the files are
              also polled for changes until the process is interrupted.

       -h     Print a terse help message.

       -l     Relaxed mode. If some data files are inaccessible since will not fail completely.

       -m     Disable mmap(2), use read(2) instead to access state and data files.  Note that for
              certain  smaller io operations read(2) may be used even if this option has not been
              given.

       -n     Do not update the .since file which keeps track of file growth.

       -q     Make the utility operate more quietly.

       -s filename
              Specify the state file explicitly. Using this option will also disable the  use  of
              fallback state files.

       -v     Increase the verbosity. This option can be given multiple times.

       -x     Ignore file arguments which have compressed extensions.

       -z     Discard output. Similar to redirecting the output to /dev/null, but faster. If used
              in conjunction with the -f option, only the initial output will be discarded.

FILES

       .since

              State file recording the length of the previously displayed files.  The location of
              the  file can be set on the command line using the -s option. If this option is not
              given, since will check the SINCE environment variable  for  the  location  of  the
              state  file.  If the SINCE environment variable has not been set since will use the
              HOME environment variable and store the information in the file  $HOME/.since.   If
              the  HOME  variable  is  not set, since will use a getpwuid(3) lookup. If all these
              fail will use the file /tmp/since.

BUGS

       since uses the inode of a file as its key, if  that  inode  is  recycled  since  will  get
       confused.   since  is  not  particularly  efficient when storing or looking up the stat(2)
       information. Functionality equivalent to since can probably be achieved with a  number  of
       trivial shell scripts.

COPYING

       since  may  only be used, distributed and modified in accordance with the terms of the GPL
       (GNU General Public License) version 3 or newer as published by  the  FSF  (Free  Software
       Foundation).

SEE ALSO

       tail(1), stat(2).