SINCE(1) User Manuals SINCE(1)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 updat-
ing 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 inter-
rupted.
-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 ini-
tial 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).
Linux JULY 1998 SINCE(1)
Check Out this Related Man Page
TAIL(1) User Commands TAIL(1)NAME
tail - output the last part of files
SYNOPSIS
tail [OPTION]... [FILE]...
DESCRIPTION
Print the last 10 lines of each FILE to standard output. With more than one FILE, precede each with a header giving the file name. With
no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-c, --bytes=K
output the last K bytes; or use -c +K to output bytes starting with the Kth of each file
-f, --follow[={name|descriptor}]
output appended data as the file grows;
an absent option argument means 'descriptor'
-F same as --follow=name --retry
-n, --lines=K
output the last K lines, instead of the last 10; or use -n +K to output starting with the Kth
--max-unchanged-stats=N
with --follow=name, reopen a FILE which has not
changed size after N (default 5) iterations to see if it has been unlinked or renamed (this is the usual case of rotated log files);
with inotify, this option is rarely useful
--pid=PID
with -f, terminate after process ID, PID dies
-q, --quiet, --silent
never output headers giving file names
--retry
keep trying to open a file if it is inaccessible
-s, --sleep-interval=N
with -f, sleep for approximately N seconds (default 1.0) between iterations; with inotify and --pid=P, check process P at least once
every N seconds
-v, --verbose
always output headers giving file names
--help display this help and exit
--version
output version information and exit
If the first character of K (the number of bytes or lines) is a '+', print beginning with the Kth item from the start of each file, other-
wise, print the last K items in the file. K may have a multiplier suffix: b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024, GB
1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y.
With --follow (-f), tail defaults to following the file descriptor, which means that even if a tail'ed file is renamed, tail will continue
to track its end. This default behavior is not desirable when you really want to track the actual name of the file, not the file descrip-
tor (e.g., log rotation). Use --follow=name in that case. That causes tail to track the named file in a way that accommodates renaming,
removal and creation.
GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report tail translation bugs to <http://translationproject.org/team/>
AUTHOR
Written by Paul Rubin, David MacKenzie, Ian Lance Taylor, and Jim Meyering.
COPYRIGHT
Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
The full documentation for tail is maintained as a Texinfo manual. If the info and tail programs are properly installed at your site, the
command
info coreutils 'tail invocation'
should give you access to the complete manual.
GNU coreutils 8.22 June 2014 TAIL(1)