Perl Programming/Keywords/tr
The tr keyword
tr is the transiteration operator and equivalent to y.
Syntax
tr///
Examples

$tmp = "909135790159";
print $tmp . "\n";
$tmp =~ tr/13579/24680/;
print $tmp . "\n";
replaces the respective characters in the first parametre with the corresponding characters in the second parametre:
909135790159 000246800260