brock@montreat:~/csci434$ egrep "0*10*"
00010000
001100
brock@montreat:~/csci434$ egrep "^0*10*$"
00010000
001100
1
brock@montreat:~/csci434$ egrep "a|b"
cat
dog
brock@montreat:~/csci434$ egrep "a+b"
aaab
baby
brock@montreat:~/csci434$ egrep "a.b"
ab
axb
brock@montreat:~/csci434$ egrep "[a-e]"
fizz
apple
e
brock@montreat:~/csci434$ egrep "[ae]"
bbb
apple
brock@montreat:~/csci434$ egrep "[[:punct:]]"
Hello?
Hi there
^
#
a
!
brock@montreat:~/csci434$ egrep "cat"
Where is that cat?
brock@montreat:~/csci434$ egrep "^cat$"
Where is that cat?
cat
brock@montreat:~/csci434$ egrep "[cat]"
cow
dog
brock@montreat:~/csci434$ egrep "[^cat]"
hello
aaaaaaa
brock@montreat:~/csci434$ egrep "[aeiou]"
frgt vwls
remember
brock@montreat:~/csci434$ egrep "ca?t"
cat
caat
brock@montreat:~/csci434$ egrep "ca+t"
cat
caat
brock@montreat:~/csci434$ egrep "ca{3}t"
cat
caaat
brock@montreat:~/csci434$ egrep "ab*c"
abbbbc
brock@montreat:~/csci434$ egrep "a(b)*c"
abbbbc
brock@montreat:~/csci434$ egrep "a\(b\)*c"
abbbbc
aac
ac
a(bc
a(b)))))c
brock@montreat:~/csci434$ egrep "ab+c"
abc
ac
brock@montreat:~/csci434$ egrep "a|c+"
cc
a
a
brock@montreat:~/csci434$ egrep "(a*) x \1"
aaaa x
aaaa x a
aaaa x aaaa
brock@montreat:~/csci434$ grep -q a
bbbb
brock@montreat:~/csci434$ echo $?
1
brock@montreat:~/csci434$ grep -q a
a
brock@montreat:~/csci434$ echo $?
0
brock@montreat:~/csci434$ python3
Python 3.6.8 (default, Jan 14 2019, 11:02:34) 
[GCC 8.0.1 20180414 (experimental) [trunk revision 259383]] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> m = re.search('3', '434')
>>> m
<_sre.SRE_Match object; span=(1, 2), match='3'>
>>> m.group(0)
'3'
>>> p = re.compile('[a-z]+')
>>> print(p.match('2019'))
None
>>> print(p.match('abc'))
<_sre.SRE_Match object; span=(0, 3), match='abc'>
>>> m = p.match('abc')
>>> m.group()
'abc'
>>> m.start()
0
>>> m.end()
3