AWK是ERE的吗

rpbear

awk应该是使用拓展正则表达式的吧，那为什么我下面的那个匹配诸如1988-12-15这样的年份的正则表达式不匹配呢？
代码如下

1. #! /bin/sh
   
2. 
   
3. awk '
   
4. BEGIN {
   
5.         mouthstr = "jan,feb,mar,apr,may"
   
6.         mouthstr = mouthstr ",june,nuly,aug,sept,oct,nov,dec"
   
7.        
   
8.         split(mouthstr,mouth,",")
   
9.         printf "input->"
   
10. }
    
11. $1 ~ /^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$/{
    
12.         split($1,date,"-")
    
13.         print date[1]," ",mouth[date[2]]," ",date[3]
    
14.         printf "input->"
    
15.         next
    
16. }
    
17. END{
    
18.         print "END"
    
19. }'

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lkk2003rty

回复 1# rpbear

1. 
   
2. [oracle@s12071 ~]$ echo "1988-12-15" | awk --posix '/^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$/'
   
3. 1988-12-15
   
4. [oracle@s12071 ~]$ echo "1988-12-15" | awk '/^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$/'
   
5. [oracle@s12071 `]$

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Shell_HAT

1. echo "1988-12-15" | awk --re-interval '/^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$/'

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rpbear

上面两个选项确实都可以
--re-interval Enable the use of interval expressions in regular expression matching (see Regular Expressions, below). Interval expressions were not traditionally available in the AWK language. The POSIX standard added them, to make awk and egrep consistent with each other. However, their use is likely to break old AWK programs, so gawk only provides them if they are requested with this option, or when --posix is specified.回复 3# Shell_HAT

yjwan

awk  默认不支持posix 标准的    也是默认情况下 {}这样的posix标准的正则表达式是无效的

可以加一个参数实现

     -W re-interval
       --re-interval
              Enable the use of interval expressions in regular expression matching (see Regular Expressions, below).  Interval expressions were not tradition-ally  available  in  the  AWK  language.  The POSIX standard added them, to make awk and egrep consistent with each other.  However, their use is likely to break old AWK programs, so gawk only provides them if they are requested with this option, or when --posix is specified.

用--posix参数 效果类似

bbgg1983

不错

oldoger

不懂问男人

linuxocp

我一般都是这样的
alias awk='awk -W posix'
还有就是grep
扩展的是egrep或者是grep -E