Computer Science
TAIL(1) TAIL(1)
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 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, option-
ally 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 indi-
cate 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.
FSF GNU Text Utilities 1
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