The `tail` command is a fundamental utility in Linux used to display the last few lines of a text file. It's particularly useful for monitoring log files in real-time. By default, `tail` shows the last 10 lines of a file, but this can be adjusted using the `-n` flag. It's often paired with the `-f` option to track changes to a file as they occur. This is invaluable for observing live updates, such as log entries, in applications or system processes. `tail` aids in diagnosing issues, tracking activities, and gaining insights into ongoing processes. Its simplicity and effectiveness make it an indispensable tool for administrators, developers, and anyone working with Linux systems.
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 suf‐
fix: 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 Mey‐
ering.
COPYRIGHT
Copyright © 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 April 2018 TAIL(1)