bash: integer to string, split and join with delimeter

Question

I'm newbie in 'sh'. Is it possible to:

#!/usr/bin/env ruby
i=123
i.to_s.split('').join('.') #=> "1.2.3"

I've tried something but didn't succeed:

i=123
IFS='' read -a array <<< "$i"
echo $array #=> "123"

Answer 1

You could use fold and paste:

$ i=123
$ echo $i | fold -w1 | paste -sd.
1.2.3
$ i=1234567890
$ echo $i | fold -w1 | paste -sd.
1.2.3.4.5.6.7.8.9.0

Answer 2

Try this:

sed -r 's/\B/./g' <<< "$i"

Your sed needs to be able to handle extended regular expressions (option -r) for this, though.