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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。 |
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正则表达式元字符
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'
class="">$ cat re-fileI had a lovely time on our little picnic.
Lovers were all around us. It is springtime. Oh
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them? I can only hope love.
is forever. I live for you. It's hard to get back in the
groove.
class="">$ cat linux.txtLinux is a good
god assdxw bcvnbvbjk
greatttttt wexcvxc
operaaaating dhfghfvx
gooodfs awrerdxxhkl
gdsystem awxxxx
glad
good
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
匹配love结尾的所有行
匹配以l开头,中间包含两个字符,结尾是e的所有行
匹配0个或多个空行,后面是love的字符
匹配love或Love
匹配A-Z的字母,其次是ove
匹配不在A-Z范围内的任何字符行,所有的小写字符
匹配love
匹配空格
匹配任意字符
前面o字符重复2到4次
重复o字符至少2次
重复0字符最多2次
重复前一个字符一个或一个以上
或,查找多个字符串
分组过滤匹配
class="">$ grep '^love' re-filelove, how much I adore you. Do you know
class="">$ grep 'love$' re-fileclover. Did you see them? I can only hope love.
class="">$ grep 'l..e' re-fileI had a lovely time on our little picnic.
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them? I can only hope love.
is forever. I live for you. It's hard to get back in the
class="">$ grep ' *love' re-fileI had a lovely time on our little picnic.
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them? I can only hope 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. Oh
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them? I can only hope love.
class="">$ grep '[A-Z]ove' re-fileLovers were all around us. It is springtime. Oh
class="">$ grep '[^A-Z]' re-fileI had a lovely time on our little picnic.
Lovers were all around us. It is springtime. Oh
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them? I can only hope love.
is forever. I live for you. It's hard to get back in the
groove.
class="">$ grep 'love\.' re-fileclover. Did you see them? I can only hope love.
class="">$ grep '^$' re-file
class="">$ grep '.*' re-fileI had a lovely time on our little picnic.
Lovers were all around us. It is springtime. Oh
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them? I can only hope love.
is forever. I live for you. It's hard to get back in the
groove.
class="">$ grep 'o\{2,4\}' re-filegroove.
class="">$ grep 'o\{2,\}' re-filegroove.
class="">$ grep 'o\{,2\}' re-fileI had a lovely time on our little picnic.
Lovers were all around us. It is springtime. Oh
love, how much I adore you. Do you know
the extent of my love? Oh, by the way, I think
I lost my gloves somewhere out in that field of
clover. Did you see them? I can only hope love.
is forever. I live for you. It's hard to get back in the
groove.
class="">$ egrep "go+d" linux.txtLinux is a good
god assdxw bcvnbvbjk
gooodfs awrerdxxhkl
good#####0个或者一个字符ansheng@Ubuntu:/tmp$ egrep "go?d" linux.txt
god assdxw bcvnbvbjk
gdsystem awxxxx
class="">$ egrep "gd|good" linux.txtLinux is a good
gdsystem awxxxx
good
class="">$ egrep "g(la|oo)d" linux.txtLinux is a good
glad
good