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- NAME
-
tail - output the last part of files
- SYNOPSIS
-
tail [-c [+]N[bkm]] [-n [+]N] [-fqv] [-bytes=[+]N[bkm]]
[-lines=[+]N] [-follow] [-quiet] [-silent]
[-verbose] [-help] [-version] [file...] tail [{-,+}Nbcfklmqv]
[file...]
- DESCRIPTION
-
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.
- b
- 512-byte blocks.
- k
- 1-kilobyte blocks.
- 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 when- ever 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.
- -help
- Print a usage message and exit with a status code indicating
success.
- -version
- Print version information on standard output then exit.
- EXAMPLES
-
Let's watch syslog:
tail -f /var/log/messages
Checking on mail deliveries
tail -f /var/log/maillog
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