Saturday, December 11, 2010

tail

TAIL(1)                          User Commands                         TAIL(1)



NAME
tail - output the last part of files

SYNOPSIS
tail [OPTION]... [FILE]...

DESCRIPTION
Print the last 10 lines of each FILE to standard output. With more
than one FILE, precede each with a header giving the file name. With
no FILE, or when FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options
too.

-c, --bytes=N
output the last N bytes; alternatively, use +N to output bytes
starting with the Nth of each file

-f, --follow[={name|descriptor}]
output appended data as the file grows; -f, --follow, and --fol‐
low=descriptor are equivalent

-F same as --follow=name --retry

-n, --lines=N
output the last N lines, instead of the last 10; or use +N to
output lines starting with the Nth

--max-unchanged-stats=N
with --follow=name, reopen a FILE which has not changed size
after N (default 5) iterations to see if it has been unlinked or
renamed (this is the usual case of rotated log files)

--pid=PID
with -f, terminate after process ID, PID dies

-q, --quiet, --silent
never output headers giving file names

--retry
keep trying to open a file even when it is or becomes inaccessi‐
ble; useful when following by name, i.e., with --follow=name

-s, --sleep-interval=S
with -f, sleep for approximately S seconds (default 1.0) between
iterations

-v, --verbose
always output headers giving file names

--help display this help and exit

--version
output version information and exit

If the first character of N (the number of bytes or lines) is a `+',
print beginning with the Nth item from the start of each file, other‐
wise, print the last N items in the file. N may have a multiplier suf‐
fix: b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024, GB
1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y.

With --follow (-f), tail defaults to following the file descriptor,
which means that even if a tail'ed file is renamed, tail will continue
to track its end. This default behavior is not desirable when you
really want to track the actual name of the file, not the file descrip‐
tor (e.g., log rotation). Use --follow=name in that case. That causes
tail to track the named file by reopening it periodically to see if it
has been removed and recreated by some other program.

AUTHOR
Written by Paul Rubin, David MacKenzie, Ian Lance Taylor, and Jim Mey‐
ering.

REPORTING BUGS
Report tail bugs to bug-coreutils@gnu.org
GNU coreutils home page:
General help using GNU software:

COPYRIGHT
Copyright © 2009 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
The full documentation for tail is maintained as a Texinfo manual. If
the info and tail programs are properly installed at your site, the
command

info coreutils 'tail invocation'

should give you access to the complete manual.



GNU coreutils 7.4 September 2010 TAIL(1)

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