> > Obviously Perl needs to escape the backslash inside a regex
> not after interpolation of variables like $bs
I have to correct myself, it depends on the side of the substitution
- the right side is a simple doublequoted string, so after interpolation no escaping
- but the left side is a regex with two levels of escaping
- string interpolation with escaping first, i.e. \$bs won't be interpolated
- regex interpretation with escaping first, i.e. /\*/ is not a quantifier but literal * same with /$bs*/
compare
d:\>perl -E"for $x (qw/C:\berrybrew\test C:\berrybrew /) {$_=$x; $bs=c
+hr(92); s#$bs$bs#<${bs}>#g; say}"
C:<\>berrybrew<\>test
C:<\>berrybrew
d:\>
or to eliminate the Win command line
use v5.12;
use warnings;
use Data::Dump;
my $bs=chr(92);
for my $x (qw/C:\berrybrew\test C:\berrybrew /) {
$_=$x;
s#$bs$bs#<${bs}>#g;
say;
#ddx $_;
}
$_='$bs';
s/\$bs/<$&>/;
say;
C:<\>berrybrew<\>test
C:<\>berrybrew
<$bs>
so this might be the OPs original problem
see also
s/RegEx/substitutions/: Variable interpolation and when to use /e - modifiers
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