Linux重要命令之—grep&&cut
grep 的基本用法，找出字符串所在行：
[buhuipao@localhost ~]$ echo -e "this is a word \n next line." | grep word
this is a word
找到字符串所在行，-i 忽略大小写，-n 打印为行号，–color=auto 颜色标记：
[buhuipao@localhost ~]$ grep -i -n drupal drupal7/install.php --color=auto
5: * Initiates a browser-based installation of Drupal.
9: * Defines the root directory of the Drupal installation.
11:define('DRUPAL_ROOT', getcwd());
20: print 'Your PHP installation is too old. Drupal requires at least PHP 5.2.4. See the <a href="http://drupal.org/requirements">system requirements</a> page for more information.';
25:require_once DRUPAL_ROOT . '/includes/install.core.inc';
26:install_drupal();
使用正则表达式：
[buhuipao@localhost ~]$ grep -E "[a-z]+" script/Readme.txt #使用-E， 利用正则表达式，找出所有小写字符
Here some useful scripts ,you can use it for free!
还可以用egrep：
[buhuipao@localhost ~]$ egrep "[a-z]+" script/Readme.txt
Here some useful scripts ,you can use it for free!
-o 只输出匹配字符串：
[buhuipao@localhost ~]$ grep -o useful script/Readme.txt
useful
-v 将匹配的结果反转：
[buhuipao@localhost ~]$ cat test.txt
NO.1 first line
NO.2 second line
NO.3 last line
[buhuipao@localhost ~]$ grep -v NO.2 test.txt
NO.1 first line
NO.3 last line
cut基本用法：
[buhuipao@localhost 4]$ cat test.data
NO name Mark Percent
1 hewen 88 90
2 huazai 34 90
3 cengbu 44 98
4 pipi 83 78
[buhuipao@localhost 4]$ cut -f 2,4 test.data
name Percent
hewen 90
huazai 90
cengbu 98
pipi 78
-d 自定义分割符：
[buhuipao@localhost 4]$ cat test1.data
NO ;Name ;Mark ; Percent
1 ;hewen ;88 ; 90
2; huazai;34 ; 90
3 ;cengbu ;44 ; 98
4; pipi;83 ;78
[buhuipao@localhost 4]$ cut -f 3 -d";" test1.data
Mark
88
34
44
83
切割一段字符：
[buhuipao@localhost 4]$ cat test2.data
fdsfasffdasdsafadsf
fdasfsafdsafdsafdf
klkliofikfkffklfff
2943040344043444dd
[buhuipao@localhost 4]$ cut -c 1-5 test2.data
fdsfa
fdasf
klkli
29430
cut 补充：
cut -c -5 test2.data #切割每一行第一个到第五个字符
cut -c 5- test2.data #切割每一行第五个到最后一个字符
cut -c1-3,8-11 test2.data --output-delimiter ";" #切割两段字符串，并且用；隔开