Q:\>perl -le "($x = 'foo') =~ /.(.)/g; print $1; $x = 'bar'; print $1"
o
a
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wow. didn't expect that.

betterworld and i just tried out some other examples, and it seems that the string buffer is not really emptied.

$ perl -MData::Dumper -we'$Data::Dumper::Useqq = 1;
($x = "fou") =~ /.(..)/g; print Dumper $1; $x = "b"; print Dumper $1;
'
$VAR1 = "ou";
$VAR1 = "\0u";
$ perl -MData::Dumper -we'$Data::Dumper::Useqq = 1;
($x = "fou") =~ /.(..)/g; print Dumper $1; $x = "ba"; print Dumper $1;
'
$VAR1 = "ou";
$VAR1 = "a\0";
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so $1 just outputs the second and third character of the string, and in the first example you see the remains of the string 'fou'