Process columns in bash

Question

I would like to substitute characters in even columns with a different char, like this (with space):

In:

hello

Out:

h l o

How can I do this?

Answer 1

cat readme.txt | sed -e "s/\(.\)./\1 /g"

EDIT: I noticed the slashes is hidden unless I used code style. Fixed.

Answer 2

This will do it:

awk '{for(i=1;i<=length;i+=2) printf("%c ", substr($0, i, 1)); printf "\n"}' <filename>

awk processes each line in turn, the for loop processes every other character and prints it followed by a space

Answer 3

sed 's/(.)./\1 /g'

I may be missing backslashes for the parentheses.

Answer 4

Use extended regex option in sed:

sed -r 's;(.).;\1 ;g' input-file