tail - output the last part of files
tail [-c [+]N[bkm]] [-n [+]N] [-fqv] [--bytes=[+]N[bkm]] [--lines=[+]N] [--follow] [--quiet] [--silent] [--verbose] [--help] [--version] [file...]
tail [{-,+}Nbcfklmqv] [file...]
This documentation is no longer being maintained and may be inaccurate or incomplete. The Texinfo documentation is now the authoritative source.
This manual page documents the GNU version of tail. tail prints the last part (10 lines by default) of each given file; it reads from standard input if no files are given or when a filename of ’-’ is encountered. If more than one file is given, it prints a header consisting of the file’s name enclosed in ’==>’ and ’<==’ before the output for each file.
The GNU tail can output any amount of data, unlike the Unix version, which uses a fixed size buffer. It has no -r option (print in reverse). Reversing a file is really a different job from printing the end of a file; the BSD tail can only reverse files that are at most as large as its buffer, which is typically 32k. A reliable and more versatile way to reverse files is the GNU tac command.
OPTIONS
tail accepts two option formats: the new one, in which
numbers are arguments to the option letters, and the old
one, in which a ’+’ or ’-’ and
optional number precede any option letters.
If a number
(’N’) starts with a ’+’, tail
begins printing with the Nth item from the start of each
file, instead of from the end.
-c N, --bytes N
Tail by N bytes. N is a nonzero integer, optionally followed by one of the following characters to specify a different unit.
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b |
512-byte blocks. |
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k |
1-kilobyte blocks. |
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m |
1-megabyte blocks. |
-f, --follow
Loop forever trying to read more characters at the end of the file, on the assumption that the file is growing. Ignored if reading from a pipe. If more than one file is given, tail prints a header whenever it gets output from a different file, to indicate which file that output is from.
-l, -n N, --lines N
Tail by N lines. -l is only recognized using the old option format.
-q, --quiet, --silent
Never print filename headers.
-v, --verbose
Always print filename headers.
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--help |
Print a usage message and exit with a status code indicating success. |
--version
Print version information on standard output then exit.