dw_dev_training | Strip tab characters from multiple text files and replace them with spaces (or something else)

I switch between Gedit, Notepad++, and vim fairly often depending on what I'm doing and whose computer I'm on. Sometimes I end up with tab characters where I really wanted four spaces, mainly when I'm using vim and I haven't figured out how to get vim to not do this. Gedit and Notepad++ have settings to use spaces instead of tabs, so there's no issue there.

Either I don't notice the tab characters until after I've put lots of them in the file I'm editing, or I'm editing a file from someone else whose editor uses tab characters for indentation. I know its not a big deal to some people, but tab indentation mixed with space indentation is a huge pet peeve of mine.

Thus, a perl script was born:

#!/usr/bin/perl -w

use File::Copy;

# This script replaces tab characters in a file with four spaces, or whatever else you want

$num_args = $#ARGV + 1;
$num_warnings = 0;
$tab_replace = "    ";  # Change this to whatever you want in place of tabs

if ( $num_args == 0 ) {
    print "usage: strip-tabs.pl file1 [file2, file3...]\n";
    exit;
}

# Have files to parse...
for my $f ( 0 .. ($num_args - 1) ) {
    if ( open(INPUTFILE, "<$ARGV[$f]") ) {
       if ( open(OUTPUTFILE, ">$ARGV[$f]~") ) {
           # Start parsing the file
           while ( my $line = <INPUTFILE> ) {
               $line =~ s/\t/$tab_replace/g;
               print OUTPUTFILE $line;
           }
           # Copy over original file here
           close(OUTPUTFILE);
           close(INPUTFILE);
           if ( !move("$ARGV[$f]~", $ARGV[$f]) ) {
               print "Could not write output to file $ARGV[$f]: $!\n";
               $num_warnings += 1;
           }
       }
       else {
           close(INPUTFILE);
           print "Could not create output file for $ARGV[$f]: $!\n";
           $num_warnings += 1;
       }
    }
    else {
        print "Could not open $ARGV[$f] for reading: $!\n";
        $num_warnings += 1;
    }
}
die "$num_warnings warnings encountered during file operation." unless $num_warnings == 0;

View Gist (strip-tabs.pl)

Feel free to gank away if you find it useful!

Flat | Top-Level Comments Only

Cool, thanks for sharing!

Another way of doing this is using sed, like this:

sed -ie 's/\t/ /g' yourfile.pl

That will replace all tabs with four spaces in yourfile.pl. You can do it in all files of a certain type with something like this:

find -name \*.pl -exec sed -ie 's/\t/ /g' {} \;

That will find all Perl files (starting in the current directory and going down, so it'll recurse into any subdirectories) and replace the tabs with spaces.

These work from a Linux/Mac command line. Windows, you're out of luck.

Edited 2012-02-03 20:34 (UTC)

Neat! And quite a bit more efficient! :) I'm always amazed at how many different ways there are to accomplish a given task on *nix-systems.

I spent many years as a Windows client-server application developer in VB6 and VB.NET. One-liners don't exist there, and so usually my brain doesn't go there! I'm trying to broaden my horizons though *g*.

There's definitely a lot of ways to accomplish any given task in the *nix environment. One of the Perl mottos is "TMTOWDTI" (There's More Than One Way To Do It), but in a lot of ways that's really true of the Unix culture that Perl grew out of. =)

The settings you're looking for in vim are expandtab (convert tabs to spaces), tabstop (how many spaces a tab counts for), and shiftwidth (how many spaces an indent should be). In my case, I want a four space indent using spaces not tabs, so I have this line in my .vimrc file:

    set expandtab tabstop=4 shiftwidth=4

This article in the vim wiki elaborates a bit more.

Thanks for posting this! Tabs in source files are the bane of my existence too. ^_^;

Thank you so much!! I knew there had to be a way to change tab settings in vim.

This just made my morning. :D

Yaaaay, so glad to hear! \o/ I think there's a way to do almost anything in vim, but sometimes the path to get there can be a little bit arcane. =)

There's a

command_liners community, if you like.

Another way of doing this is using sed, like this:

sed -ie 's/\t/ /g' yourfile.pl

Perl also has an -i switch (I think due, in part, to its originally having to compete with the established sed).

So you could boil down the script to something like perl -i -pe "s/\t/ /g" file1 file2 file3 .

Edited 2012-02-06 10:10 (UTC)

Strip tab characters from multiple text files and replace them with spaces (or something else)

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