tail - output the last part of files


tail [OPTION]... [FILE]...


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.

keep trying to open a file even if it is inaccessible when tail starts or if it becomes inaccessible later; useful when following by name, i.e., with --follow=name
-c, --bytes=N
output the last N bytes
-f, --follow[={name|descriptor}]
output appended data as the file grows; -f, --follow, and --follow=descriptor are equivalent
same as --follow=name --retry
-n, --lines=N
output the last N lines, instead of the last 10
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 -f, terminate after process ID, PID dies
-q, --quiet, --silent
never output headers giving file names
-s, --sleep-interval=S
with -f, sleep for approximately S seconds (default 1.0) between iterations.
-v, --verbose
always output headers giving file names
display this help and exit
output version information and exit

If the first character of N (the number of bytes or lines) is a `+', print beginning with the Nth item from the start of each file, otherwise, print the last N items in the file. N may have a multiplier suffix: b 512, k 1024, m 1024*1024.

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 descriptor (e.g., log rotation). Use --follow=name in that case. That causes tail to track the named file by reopening it periodically to see if it has been removed and recreated by some other program.


On older systems, the leading `-' can be replaced by `+' in the obsolete option syntax with the same meaning as in counts, and obsolete usage overrides normal usage when the two conflict. This obsolete behavior can be enabled or disabled with the `_POSIX2_VERSION' environment variable, but portable scripts should avoid commands whose behavior depends on this variable.
For example, use `tail -- - main.c' or `tail main.c' rather than the ambiguous `tail - main.c', `tail -c4' or `tail -c 10 4' rather than the ambiguous `tail -c 4', and `tail ./+4' or `tail -n +4' rather than the ambiguous `tail +4'. You can work around those compatibility problems by setting `_POSIX2_VERSION=199209' in your environment.


Written by Paul Rubin, David MacKenzie, Ian Lance Taylor, and Jim Meyering.


Report bugs to <bug-coreutils@gnu.org>. Copyright © 2006 Free Software Foundation, Inc.
This is free software. You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to the extent permitted by law.


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 tail

should give you access to the complete manual.