- grep love 1.txt
- /^love/
- /love$/
- /l.ve/
- /lo*ve/
- /[Ll]ove/
- /love[a-z]/
- /love[^a-zA-Z0-9]
- /.*/
- /^$/
- /^[A-Z]..$"/
- /^[A-Z][a-z]*3[0-5]/
- /[a-z]*\."/
- /^*[A-Z][a-z][a-z]$"/
- /^*[A-Za-z]*[^,][A-Za-z]*$/
- /\<fourth\>/
- /\<f.*th\> /
- /5{2}2{3}\./
- /^[\t]*$/
- /^#/
- /^[\t]*#/
- :1,$ s/\([Oo]ccur\)ence/\1rence/
- :1,$ s /\(square\) and \(fair\)/\2 and \1/
[root@localhost ~]# grep "^$" 1.txt
[root@localhost ~]# grep ".*" 1.txt
#qian
#yoa
#huang
kai
kong
cai
[root@localhost ~]# grep "^$" 1.txt
[root@localhost ~]# grep "[A-Z]..$" 1.txt
[root@localhost ~]# grep "[^A-Z]..$" 1.txt
#qian
#yoa
#huang
kai
kong
cai
duo
[root@localhost ~]# grep "^[A-Z]..$" 1.txt
[root@localhost ~]# grep "^[A-Z][a-z]*3[0-5]" 1.txt
[root@localhost ~]# grep "[a-z]*\." 1.txt
l.ve
[root@localhost ~]# grep "^*[A-Z][a-z][a-z]$" 1.txt
[root@localhost ~]# grep "^*[A-Za-z]*[^,][A-Za-z]*$" 1.txt
[root@localhost ~]# grep "\<fourth\>" 1.txt
[root@localhost ~]# grep \<fourth\> 1.txt
[root@localhost ~]# grep \<f.*th\> 1.txt
[root@localhost ~]# grep "5{2}2{3}\." 1.txt
[root@localhost ~]# grep "^[\t]*$" 1.txt
[root@localhost ~]# grep "^#" 1.txt
#qian
#yoa
#huang
[root@localhost ~]# grep "^[\t]*#" 1.txt
#qian
#yoa
#huang
:1,$ s/\([Oo]ccur\)ence/\1rence/
:1,$ s /\(square\) and \(fair\)/\2 and \1/ 
