Practice the following grep commands:

grep 'cat' grepTest
  --you will find both "cat" and "vacation"

grep '^cat' grepTest 
	--find only lines start with cat

grep '\<cat\>' grepTest 
     --word boundary 

grep -i '\<cat\>' grepTest 
     -ignore the case

grep '\<ega\.att\.com\>' grepTest
     --meta character

grep '"[^"]*"' grepTest
    --find quoted string

grep 'q[^u]' grepTest
    --won't find "iraq", but will find "iraqi"

egrep '[a-z][0-9][a-z] ?[0-9][a-z][0-9]' grepTest 
    --find postal code, only if it is in small case
egrep -i '[a-z][0-9][a-z] ?[0-9][a-z][0-9]' grepTest 
    --ignore the casse

--egrep is similar to grep, but somehow some patterns only work in egrep.