1、grep "aa*" /etc/passwd匹配至少含有一个a的字符串 换成a*【等效】grep "稆糨孝汶;a*" /etc/passwdgrep "aaa*" /etc/passwd匹配至少含有两个连续a的字符串grep "aaaaa*" /etc/passwd匹配至少含有四个连续a的字符串
2、grep "r..t" /etc/passwd匹配r和t之间有两个字符的单词grep "r.*t&鳎溻趄酃quot; /etc/passwd匹配r和t之间有任意字符的单词grep ".*" /etc/passwd匹配任意字符
3、grep "r[a-z]d" /etc/passwd匹配r和d之间有一个a-z的任意字符的单词grep "[0-9]" /etc/passwd匹配任意一个数字grep "^[a-z]" /etc/passwd匹配用小写字母开头的行
4、grep "^[^a-h]" /etc/passwd匹配除开头字母为a到h的行grep "^[^a-zA-Z]" /etc/passwd匹配不用字母的所有行
5、grep "o\{2\}" /etc/passwd匹配出现两个连续的o的单词grep "[0-9]\{2\}" /etc/passwd匹配连续出现两数字的单词
6、grep "o\{2,\}" /etc/passwd匹配出现至少连续的o的单词grep "[0-9]\{2,\}" /etc/passwd匹配连续出现至少两数字的单词
