我需要匹配这个替换命令：
whatever__MATCH_THIS__whateverwhatever__AND_THIS__whateverwhatever
我正在尝试：
sed -e 's/__\(.*\)__/\{{\1}}/g' myfile
但这是热切地匹配__MATCH_THIS__whateverwhatever__AND_THIS__,产生：
whatever{{MATCH_THIS__whateverwhatever__AND_THIS}}whateverwhatever
但我想：
whatever{{MATCH_THIS}}whateverwhatever{{AND_THIS}}whateverwhatever
如何在匹配部分中指定要排除的字符串？我知道如何排除一个字符(例如[^ a])但不知道如何排除字符串.
解决方法
你需要的是一个非贪婪的正则表达式,但不幸的是sed不允许这样做.但是,它可以在perl中完成.
perl -pe 's|__(.*?)__|{{$1}}|g' <myfile
星号后面的问号表示匹配器是非贪婪的,所以不是采用它能找到的最长的匹配字符串,而是最短的.
希望有所帮助.
如果你想把它放在一个perl脚本而不是在命令行上运行,那么这样的事情就可以完成这项工作：
#! /usr/bin/perl -w
use strict; # Habit of mine
use 5.0100; # So we can use 'say'
# Save the matching expression in a variable.
# qr// tells us it's a regex-like quote (http://perldoc.perl.org/functions/qr.html)
my $regex = qr/__(.*?)__/;
# Ordinarily,I'd write this in a way I consider to be less perl-y and more readable.
# What it's doing is reading from the filename supplied on STDIN and places the
# contents of the file in $_. Then it runs the substitution on the string,before
# printing out the result.
while (<>) {
$_ =~ s/$regex/{{$1}}/g;
say $_;
}
用法很简单：
./regex myfile
whatever{{MATCH_THIS}}whateverwhatever{{AND_THIS}}whateverwhatever
这是Perl,有一百万种方法可以做到！
