正則表達式:grep
[[email protected] ~]# grep ‘root‘ /etc/passwd # 過濾出帶有‘root‘的行
[[email protected] ~]# grep ‘[0-9]‘ /etc/passwd # 過濾出帶有數字的行
[[email protected] ~]# grep ‘[a-zA-Z]‘ /etc/passwd # 過濾出帶有字母的行
[[email protected] ~]# grep ‘^$‘ /etc/passwd # 過濾出空行
[[email protected]
[[email protected] ~]# grep ‘[^0-9]‘ /etc/passwd # 過濾出不包含數字的行
[[email protected] ~]# grep ‘^[^0-9]‘ /etc/passwd # 過濾出不以數字開頭的行
[[email protected] ~]# grep ‘r.o‘ /etc/passwd # . 表示匹配任意一個字符
[[email protected]