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Linux and Unix tail command tutorial with examples

Tutorial on using tail, a UNIX and Linux command for outputting the last part of files. Examples of outputting the last ten lines of a file, limiting the number of lines, limiting the number of bytes, showing multiple files, watching a file for changes and using pipes.

Estimated reading time: 3 minutes

Table of contents

Terminal showing tail man page

What is the tail command?

The tail command is a command-line utility for outputting the last part of files given to it via standard input. It writes results to standard output. By default tail returns the last ten lines of each file that it is given. It may also be used to follow a file in real-time and watch as new lines are written to it.

How to view the last ten lines of a file

To view the last ten lines of a file pass the name of a file to the tail command. The last ten lines of the file will be printed to standard output.

tail /usr/share/dict/words
zygote's
zygotes
zygotic
zymurgy
zymurgy's
Zyrtec
Zyrtec's
Zyuganov
Zyuganov's
Zzz

How to limit the number of lines to show

To set the number of lines to show with tail pass the -n option followed by the number of lines to show.

tail -n 1 /usr/share/dict/words
Zzz 

How to limit the number of bytes to show

To limit the number of bytes shown with tail pass the -c option. Instead of limiting by number of lines this will limit by the number of bytes passed to the -c option. In the following example the output is limited to 16 bytes.

tail -c 24 /usr/share/dict/words
Zyuganov
Zyuganov's
Zzz

How to show multiple files

To show the last ten lines of multiple files pass more than one filename to the tail command. This will output the last ten lines of each file to standard output with a header indicating which file is being shown.

tail /usr/share/dict/words /usr/share/dict/french
==> /usr/share/dict/words <==
zygote's
zygotes
zygotic
zymurgy
zymurgy's
Zyrtec
Zyrtec's
Zyuganov
Zyuganov's
Zzz

==> /usr/share/dict/french <==
zoos
zouave
zouaves
zozoter
zéro
zéros
zyeuter
zézaiement
zézaiements
zézayer

To suppress the header line pass the -q option. This can be useful to combine files.

tail -q /usr/share/dict/words /usr/share/dict/french
zygote's
zygotes
zygotic
zymurgy
zymurgy's
Zyrtec
Zyrtec's
Zyuganov
Zyuganov's
Zzz
zoos
zouave
zouaves
zozoter
zéro
zéros
zyeuter
zézaiement
zézaiements
zézayer

How to watch a file for changes

To watch a file for changes with the tail command pass the -f option. This will show the last ten lines of a file and will update when new lines are added. This is commonly used to watch log files in real-time. As new lines are written to the log the console will update will new lines.

tail -f /var/log/nginx/access.log
173.169.79.32 - - [03/Oct/2016:21:20:09 +0100] "GET / HTTP/1.1" 200 2213 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/601.7.7 (KHTML, like Gecko)"
...

Newer versions of tail also support watching multiple files. As the file updates a header will show which line the update is from.

tail -f /var/log/nginx/access.log /var/log/nginx/access.log

==> /var/log/nginx/access.log <==
173.169.79.32 - - [03/Oct/2016:21:23:09 +0100] "GET /apple-touch-icon-precomposed.png HTTP/1.1" 404 162 "-" "Safari/11601.7.7 CFNetwork/760.6.3 Darwin/15.6.0 (x86_64)"

==> /var/log/nginx/error.log <==
2016/10/03 21:23:53 [error] 30632#30632: *1737 access forbidden by rule, client: 216.137.60.86, server: shapeshed.com, request: "GET /wp-login.php HTTP/1.1", host: "shapeshed.com"

How to use tail with pipes

The tail command can be piped to from other commands. In the following example the output of the ls command is piped to tail to only show the five files or folders modified the longest time ago.

ls -t /etc | tail -n 5
login.defs
request-key.conf
libao.conf
mime.types
pcmcia

Further reading

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