grep太羅嗦，用ack吧。源碼搜索的不二之選～默認排除各種版本庫，可以指定多種源文件類型。

─(~/.cheat)(ruby-1.9.3-p547@rails3.1.1)────────────────────────────────────────────────────────────────────(shuleiqin@shuleiqin-F8Vr:pts/0)─┐
└─(23:14:07 on master)──> ls                                                                                                  ──(一,12月08)─┘
alias  bash  crontab  DirectoryArchitecture  echo    Git   kill  MachineProperties  passwd  Python     Regex     tree     usermod  Vi
awk    Bash  df       du                     export  grep  less  markdown           python  README.md  shutdown  useradd  vi       zip
┌─(~/.cheat)(ruby-1.9.3-p547@rails3.1.1)────────────────────────────────────────────────────────────────────(shuleiqin@shuleiqin-F8Vr:pts/0)─┐
└─(23:14:16 on master)──> ack grep                                                                                             ──(一,12月08)─┘

grep
2:grep pattern file
5:grep -i pattern file
7:# Recursively grep for string <pattern> in folder:
8:grep -R pattern folder
11:grep -Rl {search} {path}
14:grep -Rli {search} {path}
17:grep -f pattern_file file
20:grep -v pattern file
22:# You can grep with regular expressions
23:grep "^00" file  #Match lines starting with 00
24:grep -E "[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}" file  #Find IP add
28:grep -rnw 'directory' -e "pattern"
30:# Exclude grep from your grepped output of ps.
32:ps aux | grep '[h]ttpd'
35:ps aux | grep -E --color 'bash