unix script - delimit output but character other than \n

Question

What's a simple way (e.g. no perl) to turn the output of (e.g.) ls into ":"-delimited instead of "\n"-delimited?
I'm hoping for a sed or possibly awk short one-liner, I couldn't figure out how to get those to treat \n as a character that wasn't a line-delimiter though. I know Perl regexes provide this via an option, I think /m or /s or something. Which one is it?

Answer 1

ls | tr "\n" :
ls | awk -vORS=: 1

Answer 2

maybe you can try to use tr, I think it is one char only.

ls | tr '\n' '+'

Answer 3

have you looked at the most venerable tr ?

ls | tr "\n" "." 

if I remember well.