Comments on: Hack 17. Grep Command Examples http://linux.101hacks.com/linux-commands/grep-command-examples/ Free eBook to Build a Strong Foundation in UNIX / Linux Sun, 08 Aug 2010 06:48:15 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: murali http://linux.101hacks.com/linux-commands/grep-command-examples/comment-page-1/#comment-222 murali Wed, 10 Feb 2010 00:32:55 +0000 http://linux.101hacks.com/?p=87#comment-222 hi , what is d dirrerence between a. grep "John Doe" my-file > /dev/null 2>&1 b. grep "John Doe" my-file 2>&1 > /dev/null hi ,
what is d dirrerence between
a. grep “John Doe” my-file > /dev/null 2>&1
b. grep “John Doe” my-file 2>&1 > /dev/null

]]> By: Jahman http://linux.101hacks.com/linux-commands/grep-command-examples/comment-page-1/#comment-11 Jahman Fri, 15 Jan 2010 21:08:50 +0000 http://linux.101hacks.com/?p=87#comment-11 Hi, Another tip ;), grep is very slow on UTF-8. Use "LANG=C grep ..." to increase speed. $ echo $LANG en_US.UTF-8 $ time grep '^....' /usr/share/dict/words >/dev/null real 2m16.795s user 2m10.536s sys 0m0.087s $ export LANG=C $ time grep '^....' /usr/share/dict/words >/dev/null real 0m0.031s user 0m0.028s sys 0m0.003s Source: http://rg03.wordpress.com/2009/09/09/gnu-grep-is-slow-on-utf-8/ Hi,

Another tip ;) , grep is very slow on UTF-8. Use “LANG=C grep …” to increase speed.

$ echo $LANG
en_US.UTF-8
$ time grep ‘^….’ /usr/share/dict/words >/dev/null
real 2m16.795s
user 2m10.536s
sys 0m0.087s

$ export LANG=C
$ time grep ‘^….’ /usr/share/dict/words >/dev/null
real 0m0.031s
user 0m0.028s
sys 0m0.003s

Source: http://rg03.wordpress.com/2009/09/09/gnu-grep-is-slow-on-utf-8/

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