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Regular expression

Regular expression# Unix - 噫吁兮，危乎高哉

f*y2003-01-31 08:01

1 楼

#!/usr/bin/perl
$line = "one two three...";
print "$line\n";
$line =~ s/^([^ ]+) +([^ ]+)/$2 $1/;
print "$line\n";

w*n2003-01-31 08:01

2 楼

[^ ] stands for one char which is not space.
the third line reads like: find a token (one or more non space chars),
one or more spaces, and another token, and change them to the second
token ($2), space and the first token ($1).
+ stands for one or more, () are used to capture, everything matched
in the first () is stored in $1, $2 for the second (). BTW, the ^ at
the beginning of RE stands for match beginning of the string ($line).
get a perl book or "man perlre" for details.

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