Working with strings
Grep
grep x
searches for x and outputs that line grep -i x
for case Insensitivity grep -v x
outputs all line Excluding x grep -n x
outputs with the line number grep -c x
outputs the number of occurrences of x grep x *
looks for x in all directories grep -r x /path
looks for x recursively in the path
Regex
grep, sed, awk can use regex java, py, js etc can use regex
a*
Zero or more occurrences of "a" Example fooa*bar
matches
fooaaaabar
fooabar
foobar
fooaabar
.
the dot/ single wildcard represents any ONE character in a single position
Example foo.bar
matches
fooabar
fooxbar
foocbar
and not "foobar" or "fooxybar" or "baryfoo"
.*
for ANY CHARACTER having ZERO OR MORE OCCOURENCES Example