grep命令
作用：从文本文件或管道数据流中筛选匹配的行及数据，配合正则表达式一起使用，功能更加强大。
格式:
grep [options] [pattern] [file]
１，匹配包含"ghostwu"的行
ghostwu@dev:~/linux/grep$ cat -n ghostwu.txt
my name is ghostwu
how are you
fine think you
My name is Ghostwu
what's your name?
my name is ghostwu2 ghostwu@dev:~/linux/grep$ grep "ghostwu" ghostwu.txt
my name is ghostwu
my name is ghostwu2
２，-v: 不包含，相当于取反
ghostwu@dev:~/linux/grep$ grep -v "ghostwu" ghostwu.txt
how are you
fine think you
My name is Ghostwu
what's your name? ghostwu@dev:~/linux/grep$
３，-n 添加行号
ghostwu@dev:~/linux/grep$ grep -n "ghostwu" ghostwu.txt
:my name is ghostwu
:my name is ghostwu2
ghostwu@dev:~/linux/grep$ grep -vn "ghostwu" ghostwu.txt
:how are you
:fine think you
:My name is Ghostwu
:what's your name?
:
４，-E，使用扩展的egrep命令，模式中可以用正则表达式
ghostwu@dev:~/linux/grep$ cat ghostwu.txt
my name is ghostwu
how are you
fine think you
My name is Ghostwu
what's your name?
my name is ghostwu2 ghostwu@dev:~/linux/grep$ grep -E "my|your" ghostwu.txt
my name is ghostwu
what's your name?
my name is ghostwu2
ghostwu@dev:~/linux/grep$ grep -Ev "my|your" ghostwu.txt
how are you
fine think you
My name is Ghostwu ghostwu@dev:~/linux/grep$ grep -En "my|your" ghostwu.txt
:my name is ghostwu
:what's your name?
:my name is ghostwu2
５，-i选项，不区分大小写
ghostwu@dev:~/linux/grep$ grep "ghostwu" ghostwu.txt
my name is ghostwu
my name is ghostwu2
ghostwu@dev:~/linux/grep$ grep -i "ghostwu" ghostwu.txt
my name is ghostwu
My name is Ghostwu
my name is ghostwu2
６，-c :统计匹配的行数，不是匹配字符串的次数
ghostwu@dev:~/linux/grep$ grep -c "ghostwu" ghostwu.txt ghostwu@dev:~/linux/grep$ grep -ci "ghostwu" ghostwu.txt
ghostwu@dev:~/linux/grep$ grep -c "ghostwu" ghostwu.txt ghostwu@dev:~/linux/grep$ grep "ghostwu" ghostwu.txt
my name is ghostwu, nice to meet you,ghostwu
my name is ghostwu2
ghostwu@dev:~/linux/grep$ cat -n ghostwu.txt
my name is ghostwu, nice to meet you,ghostwu
how are you
fine think you
My name is Ghostwu
what's your name?
my name is ghostwu2
７，-o: 只输出匹配到的字符串
ghostwu@dev:~/linux/grep$ grep -o "ghostwu" ghostwu.txt
ghostwu
ghostwu
ghostwu@dev:~/linux/grep$ grep -oi "ghostwu" ghostwu.txt
ghostwu
Ghostwu
ghostwu
８，-w: 只匹配过滤的单词，类似于精确匹配
ghostwu@dev:~/linux/grep$ grep -w "ghostwu" ghostwu.txt
my name is ghostwu, nice to meet you,ghostwu
ghostwu@dev:~/linux/grep$ grep -wi "ghostwu" ghostwu.txt
my name is ghostwu, nice to meet you,ghostwu
My name is Ghostwu
ghostwu@dev:~/linux/grep$ cat -n ghostwu.txt
my name is ghostwu, nice to meet you,ghostwu
how are you
fine think you
My name is Ghostwu
what's your name?
my name is ghostwu2
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
ghostwu@dev:~/linux/grep$ grep -Ev "^$|#" ghostwu.php
<?php
class Person {
public $name = 'ghostwu';
public $age = ;
public function showinfo(){
echo $this->name . PHP_EOL;
echo $this->age. PHP_EOL;
}
}
ghostwu@dev:~/linux/grep$ cat -n ghostwu.php
<?php class Person { #人名
public $name = 'ghostwu'; #年龄
public $age = ; #显示信息
public function showinfo(){
echo $this->name . PHP_EOL;
echo $this->age. PHP_EOL;
}
}