First off, tr/// does not do interpolation, strings or regular expressions.    For that you need s///g.

Your expression my $result = eval "tr/$search/$replace/"; is short for my $result = eval "\$_ =~ tr/$search/$replace/"; but it appears that there is nothing in $_.    Perhaps you meant: 

my $s = 'eabcde';

my $search = 'abcd';
my $replace = 'efgh';

eval "\$s =~ tr/$search/$replace/";

print "$search\n";
print "$replace\n";
print "$s\n";

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In reply to Re: doing tr/// on-the-fly? by jwkrahn
in thread doing tr/// on-the-fly? by Anonymous Monk

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