GREP

###GREP###

Features:

1. The ability to parse lines based on text and/or RegExes

2. Post-processor

3. Searches case-sensitively, by default

4. Searches for the text anywhere on the line

1. grep 'linux' grep1.txt

2. grep -i 'linux' grep1.txt - case-insensitive search

3. grep '^linux' grep1.txt - uses '^' anchor to anchor searches at the beginning of

lines

4. grep -i '^linux' grep1.txt

5. grep -i 'linux$' grep1.txt - uses '$' anchor to anchor searches at the end of

lines

Note: Anchors are RegEx characters (meta-characters). They're used to match at the

beginning and end of lines

6. grep '[0-9]' grep1.txt - returns lines containing at least 1 number

7. grep '[a-z]' grep1.txt

8. rpm -qa | grep grep - searches the package database for programs named 'grep'

9. rpm -qa | grep -i xorg | wc -l - returns the number of pacakges with 'xorg' in

their names

10. grep sshd messages

11. grep -v sshd messages - performs and inverted search (all but 'sshd' entries

will be returned)

12. grep -v sshd messages | grep -v gconfd

13. grep -C 2 sshd messages - returns 2 lines, above and below matching line

Note: Most, if not all, Linux programs log linearly, which means one line after

another, from the earliest to the current

Note: Use single or double quotes to specify RegExes

Also, execute 'grep' using 'egrep' when RegExes are being used