How can I convert tabs to spaces in every file of a directory?

Question

How can I convert tabs to spaces in every file of a directory (possibly recursively)?

Also, is there a way of setting the number of spaces per tab?

Answer 1

You can use the generally available pr command (man page here). For example, to convert tabs to four spaces, do this:

pr -t -e=4 file > file.expanded

• -t suppresses headers
• -e=num expands tabs to num spaces

To convert all files in a directory tree recursively, while skipping binary files:

#!/bin/bash
num=4
shopt -s globstar nullglob
for f in **/*; do
  [[ -f "$f" ]]   || continue # skip if not a regular file
  ! grep -qI "$f" && continue # skip binary files
  pr -t -e=$num "$f" > "$f.expanded.$$" && mv "$f.expanded.$$" "$f"
done

The logic for skipping binary files is from this post.

NOTE:

1. Doing this could be dangerous in a git or svn repo
2. This is not the right solution if you have code files that have tabs embedded in string literals