Summery
catはテキスト・ドキュメントを昇順で表示するのに対して、tacは降順で表示する事ができる。
※Macなどでは、標準搭載されていません。
Construction
$ tac [option] [file]
Option
-b : 区切り文字を先頭に付与する
-c : 区切り文字を正規表現として扱う
-s : 区切り文字を指定する
Sample
# エラーログを逆ソートで表示する
$ tac /var/log/apache2/error.log
Discription
NAME
tac - concatenate and print files in reverse
SYNOPSIS
tac [OPTION]... [FILE]...
DESCRIPTION
Write each FILE to standard output, last line first. With no FILE, or when FILE is -, read
standard input.
Mandatory arguments to long options are mandatory for short options too.
-b, --before
attach the separator before instead of after
-r, --regex
interpret the separator as a regular expression
-s, --separator=STRING
use STRING as the separator instead of newline
--help display this help and exit
--version
output version information and exit
GNU coreutils online help: <http: //www.gnu.org/software/coreutils> Report tac translation
bugs to <http: //translationproject.org/team>
AUTHOR
Written by Jay Lepreau and David MacKenzie.
COPYRIGHT
Copyright © 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later
<http: //gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to
the extent permitted by law.
SEE ALSO
rev(1)
The full documentation for tac is maintained as a Texinfo manual. If the info and tac pro‐
grams are properly installed at your site, the command
info coreutils 'tac invocation'
should give you access to the complete manual.