正则表达式的贪婪匹配

str="uid=100(guest) gid=100(others) groups=10(users),11(floppy)"

取 guest  others  users  floppy

正则表达式是有贪婪性的，它总是与最长的可能长度匹配，而且越是排在前面的通配符优先级越高。

 

#!/bin/bash

stra="uid=100(guest) gid=100(others) groups=10(users),11(floppy)"

strb="uid=100(guest)gid=100(others)groups=10(users),11(floppy)"

 

#floppy

echo $stra |sed 's/.*(\(.*\)).*/\1/'

echo $stra |awk '{a=substr($3,length($3)-6,6); b=substr($3,1,6); c=length($3);print a,b,c}'

#guest

echo $stra |sed 's/[^(]*(\([^)]*\)).*/\1/'

echo $stra |awk '{a=gensub(/.*\((.*)\)/,"\\1","g",$1);print a}'

#others

echo $stra |sed 's/users\|others/***&***/g'

echo $stra |sed 's/[^(]*([^)]*)[^(]*(\([^)]*\)).*/\1/'

echo $stra |sed 's/[^ ]*[ ][^(]*(\([^)]*\)).*/\1/'

#users

echo $stra |sed 's/.*[ ][^(]*(\([^)]*\)).*/\1/'

echo $stra |awk '{a=gensub(/[^(]*\(([^)]*).*/,"\\1","g",$3);print a}'

 

时间一久自己都看的晕忽忽的。。。记下来用的时候翻翻