grep [options] [pattern] [file]
１，匹配包含"linuxidc"的行
ghostwu@dev:~/linux/grep$ cat -n linuxidc.txt
my name is linuxidc
how are you
fine think you
My name is linuxidc
what's your name?
my name is linuxidc2
ghostwu@dev:~/linux/grep$ grep "linuxidc" ghostwu.txt
my name is linuxidc
my name is linuxidc2
２，-v: 不包含，相当于取反
linuxidc@dev:~/linux/grep$ grep -v "linuxidc" ghostwu.txt
how are you
fine think you
My name is linuxidc
what's your name?
linuxidc@dev:~/linux/grep$
３，-n 添加行号
linuxidc@dev:~/linux/grep$ grep -n "linuxidc" ghostwu.txt
1:my name is linuxidc
6:my name is linuxidc2
ghostwu@dev:~/linux/grep$ grep -vn "linuxidc" ghostwu.txt
2:how are you
3:fine think you
4:My name is linuxidc
5:what's your name?
7:
４，-E，使用扩展的egrep命令，模式中可以用正则表达式
linuxidc@dev:~/linux/grep$ cat linuxidc.txt
my name is linuxidc
how are you
fine think you
My name is linuxidc
what's your name?
my name is linuxidc2
ghostwu@dev:~/linux/grep$ grep -E "my|your" linuxidc.txt
my name is linuxidc
what's your name?
my name is linuxidc2
ghostwu@dev:~/linux/grep$ grep -Ev "my|your" linuxidc.txt
how are you
fine think you
My name is linuxidc
ghostwu@dev:~/linux/grep$ grep -En "my|your" linuxidc.txt
1:my name is linuxidc
5:what's your name?
6:my name is linuxidc2
５，-i选项，不区分大小写
linuxidc@dev:~/linux/grep$ grep "linuxidc" ghostwu.txt
my name is linuxidc
my name is linuxidc2
ghostwu@dev:~/linux/grep$ grep -i "linuxidc" ghostwu.txt
my name is linuxidc
My name is linuxidc
my name is linuxidc2
６，-c :统计匹配的行数，不是匹配字符串的次数
linuxidc@dev:~/linux/grep$ grep -c "linuxidc" ghostwu.txt
2
linuxidc@dev:~/linux/grep$ grep -ci "linuxidc" ghostwu.txt
3
linuxidc@dev:~/linux/grep$ grep -c "linuxidc" ghostwu.txt
2
linuxidc@dev:~/linux/grep$ grep "linuxidc" ghostwu.txt
my name is linuxidc, nice to meet you,linuxidc
my name is linuxidc2
ghostwu@dev:~/linux/grep$ cat -n linuxidc.txt
1 my name is linuxidc, nice to meet you,linuxidc
2 how are you
3 fine think you
4 My name is linuxidc
5 what's your name?
6 my name is linuxidc2
7
７，-o: 只输出匹配到的字符串
linuxidc@dev:~/linux/grep$ grep -o "linuxidc" ghostwu.txt
linuxidc
ghostwu
linuxidc@dev:~/linux/grep$ grep -oi "linuxidc" ghostwu.txt
linuxidc
Ghostwu
linuxidc
８，-w: 只匹配过滤的单词，类似于精确匹配
linuxidc@dev:~/linux/grep$ grep -w "linuxidc" ghostwu.txt
my name is linuxidc, nice to meet you,linuxidc
ghostwu@dev:~/linux/grep$ grep -wi "linuxidc" ghostwu.txt
my name is linuxidc, nice to meet you,linuxidc
My name is linuxidc
ghostwu@dev:~/linux/grep$ cat -n linuxidc.txt
1 my name is linuxidc, nice to meet you,linuxidc
2 how are you
3 fine think you
4 My name is linuxidc
5 what's your name?
6 my name is linuxidc2
7
９，常用的一招小技巧，去除文件的注释和空行，在运维中，可以用这条命令把配置文件的空行和注释去掉，然后用管道生成。这样配置文件比较容易查看和配置
linuxidc@dev:~/linux/grep$ grep -Ev "^$|#" linuxidc.php
<?php
class Person {
public $name = 'linuxidc';
public $age = 20;
public function showinfo(){
echo $this->name . PHP_EOL;
echo $this->age. PHP_EOL;
}
}
linuxidc@dev:~/linux/grep$ cat -n linuxidc.php
1 <?php
2
3 class Person {
4
5 #人名
6 public $name = 'linuxidc';
7
8 #年龄
9 public $age = 20;
10
11 #显示信息
12 public function showinfo(){
13 echo $this->name . PHP_EOL;
14 echo $this->age. PHP_EOL;
15 }
16 }