3分钟搞定Linux系统正则表达式
发表于:2024-10-19 作者:千家信息网编辑
千家信息网最后更新 2024年10月19日,正则表达式是一种字符模式,用于在查找过程中匹配制定的字符。元字符通常在 Linux 中分为两类:Shell元字符,由Linux Shell进行解析;正则表达式元字符,由vi/grep/sed/awk等
千家信息网最后更新 2024年10月19日3分钟搞定Linux系统正则表达式
元字符通常在 Linux 中分为两类:Shell元字符,由Linux Shell进行解析;
正则表达式元字符,由vi/grep/sed/awk等文本处理工具进行解析;
正则表达式一般以文本行进行处理,在进行下面实例之前,先为grep命令设置--color参数:
正则表达式是一种字符模式,用于在查找过程中匹配制定的字符。 |
正则表达式元字符,由vi/grep/sed/awk等文本处理工具进行解析;
正则表达式一般以文本行进行处理,在进行下面实例之前,先为grep命令设置--color参数:
class="">$ alias grep='grep --color=auto'
这样每次过滤出来的字符串都会带色彩了。
在开始之前还需要做一件事情,就是创建一个测试用的re-file文件,内容如下:
class="">$ cat re-fileI had a lovely time on our little picnic.Lovers were all around us. It is springtime. Ohlove, how much I adore you. Do you knowthe extent of my love? Oh, by the way, I thinkI lost my gloves somewhere out in that field ofclover. Did you see them? I can only hope love.is forever. I live for you. It's hard to get back in thegroove.
class="">$ cat linux.txtLinux is a good god assdxw bcvnbvbjkgreatttttt wexcvxcoperaaaating dhfghfvxgooodfs awrerdxxhklgdsystem awxxxxgladgood
正则表达式元字符
特殊的元字符
扩展的正则表达式
实操
匹配以love开头的所有行
class="">$ grep '^love' re-filelove, how much I adore you. Do you know
匹配love结尾的所有行
class="">$ grep 'love$' re-fileclover. Did you see them? I can only hope love.
匹配以l开头,中间包含两个字符,结尾是e的所有行
class="">$ grep 'l..e' re-fileI had a lovely time on our little picnic.love, how much I adore you. Do you knowthe extent of my love? Oh, by the way, I thinkI lost my gloves somewhere out in that field ofclover. Did you see them? I can only hope love.is forever. I live for you. It's hard to get back in the
匹配0个或多个空行,后面是love的字符
class="">$ grep ' *love' re-fileI had a lovely time on our little picnic.love, how much I adore you. Do you knowthe extent of my love? Oh, by the way, I thinkI lost my gloves somewhere out in that field ofclover. Did you see them? I can only hope love.
匹配love或Love
class="">$ grep '[Ll]ove' re-file # 对l不区分大小写I had a lovely time on our little picnic.Lovers were all around us. It is springtime. Ohlove, how much I adore you. Do you knowthe extent of my love? Oh, by the way, I thinkI lost my gloves somewhere out in that field ofclover. Did you see them? I can only hope love.
匹配A-Z的字母,其次是ove
class="">$ grep '[A-Z]ove' re-fileLovers were all around us. It is springtime. Oh
匹配不在A-Z范围内的任何字符行,所有的小写字符
class="">$ grep '[^A-Z]' re-fileI had a lovely time on our little picnic.Lovers were all around us. It is springtime. Ohlove, how much I adore you. Do you knowthe extent of my love? Oh, by the way, I thinkI lost my gloves somewhere out in that field ofclover. Did you see them? I can only hope love.is forever. I live for you. It's hard to get back in thegroove.
匹配love
class="">$ grep 'love\.' re-fileclover. Did you see them? I can only hope love.
匹配空格
class="">$ grep '^$' re-file
匹配任意字符
class="">$ grep '.*' re-fileI had a lovely time on our little picnic.Lovers were all around us. It is springtime. Ohlove, how much I adore you. Do you knowthe extent of my love? Oh, by the way, I thinkI lost my gloves somewhere out in that field ofclover. Did you see them? I can only hope love.is forever. I live for you. It's hard to get back in thegroove.
前面o字符重复2到4次
class="">$ grep 'o\{2,4\}' re-filegroove.
重复o字符至少2次
class="">$ grep 'o\{2,\}' re-filegroove.
重复0字符最多2次
class="">$ grep 'o\{,2\}' re-fileI had a lovely time on our little picnic.Lovers were all around us. It is springtime. Ohlove, how much I adore you. Do you knowthe extent of my love? Oh, by the way, I thinkI lost my gloves somewhere out in that field ofclover. Did you see them? I can only hope love.is forever. I live for you. It's hard to get back in thegroove.
重复前一个字符一个或一个以上
class="">$ egrep "go+d" linux.txtLinux is a goodgod assdxw bcvnbvbjkgooodfs awrerdxxhklgood#####0个或者一个字符ansheng@Ubuntu:/tmp$ egrep "go?d" linux.txtgod assdxw bcvnbvbjkgdsystem awxxxx
或,查找多个字符串
class="">$ egrep "gd|good" linux.txtLinux is a goodgdsystem awxxxxgood
分组过滤匹配
class="">$ egrep "g(la|oo)d" linux.txtLinux is a goodgladgood
字符
正则
表达式
元字符
多个
字符串
开头
处理
特殊
两个
事情
以文
内容
参数
命令
大小
字母
实例
小写
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