How do you enter text before and after each character in a string in Perl?

Your example result does not put the text before spaces, so you'd need to change howlin_mouse's solution to look at non-space characters. Otherwise you'd have 1A21 21b21i21g21 21d21o21g2. Actually, I think his answer would give you 1A big dog2 since you're looking for one or more characters, but I'm not at a computer with perl to test it out.

You don't "enter" it at all. Just construct a completely new string. Break the entered string into characters, and add each character and the separators to the new string.

in case you recommend you like loop over each and each letter of each and every line, something like on a similar time as($line = record) { @letters = split //, $line; foreach $l ( @letters ) { print $l; } } or something comparable.

use a regex. string ~= s/(.)+/1$12/g