shell - How to replace one character with two characters using tr

Question

Can tr replace one character with two characters?

I am trying to replace "~" with "~ " but the output does not produce the newline.

$ echo "asdlksad ~ adlkajsd ~ 12345" | tr "~" "~
"
asdlksad ~ adlkajsd ~ 12345

Answer 1

No, tr is specifically intended to replace single characters by single characters (or, depending on command-line options, to delete characters or replace runs of a single character by one occurrence.).

sed is probably the best tool for this particular job:

$ echo "asdlksad ~ adlkajsd ~ 12345" | sed 's/~/~
/g'
asdlksad ~
 adlkajsd ~
 12345

(Note that this requires sed to interpret the backlash-n sequence as a newline character. GNU sed does this, but POSIX doesn't specify it except within a regular expression, and there are definitely older versions of sed that don't.)