01-07-2009
Like cat, there is command named 'tac' which works same as that cat, except it reverse the order.
ur script can be like:
tac f1 > f1.tmp
mv f1.tmp f1
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TAC(1) User Commands TAC(1)
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 (C) 2013 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 programs are properly installed at your site, the
command
info coreutils 'tac invocation'
should give you access to the complete manual.
GNU coreutils 8.22 June 2014 TAC(1)