tail

Examples (TL;DR)

• Show last 'num' lines in file: tail -n num file
• Show all file since line 'num': tail -n +num file
• Show last 'num' bytes in file: tail -c num file
• Keep reading file until Ctrl + C: tail -f file
• Keep reading file until Ctrl + C, even if the file is rotated: tail -F file

tldr.sh

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=[+]NUM

output the last NUM bytes; or use -c +NUM to output starting with byte NUM 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=[+]NUM

output the last NUM lines, instead of the last 10; or use -n +NUM to output starting with line NUM

--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

-z, --zero-terminated

line delimiter is NUL, not newline

--help

display this help and exit

--version

output version information and exit

NUM 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. Binary prefixes can be used, too: KiB=K, MiB=M, and so on.

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 in a way that accommodates renaming, removal and creation.

Author

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

Reporting Bugs

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>

Copyright

Copyright © 2019 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://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

head(1)

Full documentation <https://www.gnu.org/software/coreutils/tail>
or available locally via: info '(coreutils) tail invocation'

Referenced By

collectd.conf(5), ctail(1), fetchlog(1), ffbblog(1), head(1), ii(1), pmcd(1), pmdalogger(1), pmdasystemd(1), pmdaweblog(1), sdjournal(1), since(1), swatch(1), virt-tail(1).