Unix in a Nutshell, 4th Edition

Name

tail

Synopsis

    tail [options] [file]

Print the last 10 lines of the named file. Use only one of -f or -r.

The GNU/Linux and Mac OS X versions can process multiple files. In that case, the output includes a header at the beginning of each file:

    =  =>filename<=  =

Historic Options

The syntaxes shown here are the historic usage. Currently all systems continue to accept them, but the -c and -n options are preferred.

-n[k]

Begin printing at n th item from end of file. k specifies the item to count: l (lines, the default), b (blocks), or c (characters, i.e., bytes).

- k

Same as previous, but use the default count of 10.

+n[k]

Like - n, but start at n th item from beginning of file.

+ k

Like - k, but count from beginning of file.

Common Options

-ccount, --bytes=count

With a leading + on count, start count bytes from the front of the file. With a leading - or no sign, start from the end of the file.

-f[follow_spec], --follow[=follow_spec]

Don’t quit at the end of file; “follow” file as it grows. End with an INTR (usually ^C).

Only GNU/Linux allows a follow_spec. If the follow_spec is descriptor, tail follows the open file descriptor. This shows the original file, even if it is renamed or removed, and is the command’s original, default behavior. If follow_spec is name, then tail periodically reopens the file by name. This is useful in cases where filenames change, such as rotated log files.

-ncount, --lines=count

With a leading + on count, start count lines from the front of the file. With a leading