Saturday, April 9, 2011

GREP command in linux / unix

GREP command searches the file for a lines match to a string, words, or characters we pass on.
Syntax: grep [-option] 'search word' /path/to/file

Options are as follows:
  • -i : to ignore word case.
  • -r : recursively read files under each directory.
  • -w : to get the matching word only.
  • -c : to count number of lines that the search word matches.
  • -P : to use regex command within the grep command.
  • -l : to list the file names matching the search word.
  • -v : to get lines that doesn't match the search word.

Sample GREP commands:

- default grep command without using an option.
$ grep 'word' /path/to/file

- ignoring word cases and matches
$ grep -i 'word'/path/to/file

- using regex to get all the lines that matches
$ grep -P "word1|word2" /path/to/file
$ grep -P "^word3" /path/to/file

- matching the exact words in a line
$ grep -w "word" /path/to/file

- get the file names that matches the search word.
$ grep -l "init()" /path/to/file*

- invert matches to the line
$ grep -v "word" /path/to/file

- grep command combining options and uses pipe to execute next grep command.
$ grep -ivP "word1|word2" /path/to/file
$ grep -i "word" /path/to/file | grep -vP "word2"
Posted by Unknown at 5:55 PM
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2 comments:

  1. Javin @ vi editor in unixJuly 15, 2011 at 10:35 PM

    Nice post. you have indeed covered topic in detail with samples. I have also blogged my experience as grep command in unix with examples
     ,let me know how do you find it. Thanks

    ReplyDelete
  2. AkhilJanuary 12, 2012 at 7:27 PM

    Some examples on Find Command and Awk Command

    ReplyDelete

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