using wildcards

me@box:~$ cat demo.txt

the quick brown fox jumps over the lazy dog

pack my box with five dozen liquor jugs

lou played catch with the jealous cat

me@box:~$ cat demo.txt | egrep ‘the.*k’

the quick brown fox jumps over the lazy dog

me@box:~$ cat demo.txt | egrep ‘th.*e’

the quick brown fox jumps over the lazy dog

me@box:~$ cat demo.txt | egrep ‘(over )*the’

the quick brown fox jumps over the lazy dog

lou played catch with the jealous cat

me@box:~$ cat demo.txt | egrep ‘(over )+the’

the quick brown fox jumps over the lazy dog