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Text::Tabs - expand and unexpand tabs like unix expand(1) and unexpand(1)


use Text::Tabs;

$tabstop = 4;  # default = 8
@lines_without_tabs = expand(@lines_with_tabs);
@lines_with_tabs = unexpand(@lines_without_tabs);


Text::Tabs does most of what the unix utilities expand(1) and unexpand(1) do. Given a line with tabs in it, expand replaces those tabs with the appropriate number of spaces. Given a line with or without tabs in it, unexpand adds tabs when it can save bytes by doing so, like the unexpand -a command.

Unlike the old unix utilities, this module correctly accounts for any Unicode combining characters (such as diacriticals) that may occur in each line for both expansion and unexpansion. These are overstrike characters that do not increment the logical position. Make sure you have the appropriate Unicode settings enabled.


The following are exported:


The $tabstop variable controls how many column positions apart each tabstop is. The default is 8.

Please note that local($tabstop) doesn't do the right thing and if you want to use local to override $tabstop, you need to use local($Text::Tabs::tabstop).


# unexpand -a
use Text::Tabs;

while (<>) {
  print unexpand $_;

Instead of the shell's expand command, use:

perl -MText::Tabs -n -e 'print expand $_'

Instead of the shell's unexpand -a command, use:

perl -MText::Tabs -n -e 'print unexpand $_'


Text::Tabs handles only tabs ("\t") and combining characters (/\pM/). It doesn't count backwards for backspaces ("\t"), omit other non-printing control characters (/\pC/), or otherwise deal with any other zero-, half-, and full-width characters.


Copyright (C) 1996-2002,2005,2006 David Muir Sharnoff. Copyright (C) 2005 Aristotle Pagaltzis Copyright (C) 2012-2013 Google, Inc. This module may be modified, used, copied, and redistributed at your own risk. Although allowed by the preceding license, please do not publicly redistribute modified versions of this code with the name "Text::Tabs" unless it passes the unmodified Text::Tabs test suite.