Use grep and regular expressions to analyze text

1) grep 'word' filename

2)cat filename | grep 'something'

Regular expressions

1)The following example displays lines starting with the vivek only
grep ^vivek /etc/passwd

2)Find lines ending with word foo:
grep 'foo$' filename

3)Match line only containing foo:
grep '^foo$' filename

4)You can match two numeric digits (i.e. match foo11, foo12 etc):
grep 'foo[0-9][0-9]' filename