How can I convert spaces to tabs in Vim or Linux?

Question

I've looked over several questions on Stack Overflow for how to convert spaces to tabs without finding what I need. There seem to be more questions about how to convert tabs to spaces, but I'm trying to do the opposite.

In Vim I've tried :retab and :retab! without luck, but I believe those are actually for going from tabs to spaces anyways.

I tried both expand and unexpand at the command prompt without any luck.

Here is the file in question:

http://gdata-python-client.googlecode.com/hg-history/a9ed9edefd61a0ba0e18c43e448472051821003a/samples/docs/docs_v3_example.py

How can I convert leading spaces to tabs using either Vim or the shell?

Answer 1

Using Vim to expand all leading spaces (wider than 'tabstop'), you were right to use retab but first ensure 'expandtab' is reset (:verbose set ts? et? is your friend). retab takes a range, so I usually specify % to mean "the whole file".

:set tabstop=2      " To match the sample file
:set noexpandtab    " Use tabs, not spaces
:%retab!            " Retabulate the whole file

Before doing anything like this (particularly with Python files!), I usually set 'list', so that I can see the whitespace and change.

I have the following mapping in my .vimrc for this:

nnoremap    <F2> :<C-U>setlocal lcs=tab:>-,trail:-,eol:$ list! list? <CR>