|
Feb 17, 2008 at 07:01 PM |
How To Using grep.
Impress tutorial is here.
What does grep do?
* Prints lines matching a pattern or
* Prints files that match a pattern
* Searching
File contents
Program results
Using grep
* A file
* Or group of files
# grep “FINDME” file.txt
# grep “FINDME” *
* Program output
(std input)
# ls | grep “FINDME”
Options for searching
* -i – ignore case
= “FINDME” matches FindMe, FINDME, findme.
* -v – reverse lookup
= Find all non-matches
* -w – Match a word
= Spaces or punctuation must surround search string
Options for displaying results
* Normally, matching lines are displayed
* Other possibilities
= -c – count results
= -L – display files without match
= -l – display files with match
Changing formats
* -n – display line number
* -h – don't print file name
* -o – show only the matching part of the line
Useful with regular expressions
A word on Regular Expressions
* Extremely powerful and useful
* Can be confusing and difficult
* grep uses regular expressions by default
What this means to you:
Special Chars must have a '\' before them
+ * . [] () {} ? \ + - ~ ^ $
More info
* Lots more options
man grep
|
LUG How Tos 
