grep .....

yanghwanim · 04-09-2009, 07:31 PM

The power of grep.....I'm trying to understand its use...can someone explain it to me?

sycamorex · 04-09-2009, 07:44 PM

If you don't like grep man pages, please google it - there are A LOT OF tutorials on that subject.

edit: its general use is (as the man page says): to print lines matching a pattern

cheftec · 04-09-2009, 07:46 PM

http://www.ss64.com/bash/grep.html

Read that. On your level as a newbie, you'll pretty much just use it as a specifier. For example, if you

ps -A | grep firefox

you're asking the computer to give you a list of all the processes running (ps -A) but then to only show (with grep) the ones that have firefox in the name of the process.

chrism01 · 04-09-2009, 11:21 PM

And for finding strings in files:

grep <string_to-find> <file(s)-to-search>

eg

grep zxc test.dat

find all lines with 'zxc' in file test.dat

most popular switch is -i -> case-insensitive matching ie

grep -i zxc test.dat

matches 'zxc' or 'Zxc', or 'ZXc' etc etc ...

mahajan.girish · 04-10-2009, 01:08 AM

Dude, suppose u have x lines of data in sample.txt file, out of which some of the lines contains "temp" keyword , and if u want to skip that all lines contens temp, then try

cat sample.txt | grep -v "temp"

it will show only tht lines that doesnt contain temp word...

Cheers J!

yanghwanim · 05-28-2009, 05:34 PM

Thanks for the links, and help! I now understand Grep!

Thanks!