bash: How to add space in string?

Question

I have a string like this:

string="aaa-bbb"

But I want to add space before char '-', so I want this:

aaa -bbb

I tried a lot of things, but I can't add space there. I tried with echo $string | tr '-' ' -', and some other stuff, but it didn't work...

I have Linux Mint: GNU bash, version 4.3.8(1)

Answer 1

No need to call sed, use string substitution native in BASH:

$ foo="abc-def-ghi"
$ echo "${foo//-/ -}"
abc -def -ghi

Note the two slashes after the variable name: the first slash replaces the first occurrence, where two slashes replace every occurrence.