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Miko O'Sullivan


String::Util -- String processing utilities


  use String::Util ':all';
  # "crunch" whitespace and remove leading/trailing whitespace
  $val = crunch($val);
  # does this value have "content", i.e. it's defined
  # and has something besides whitespace?
  if (hascontent $val) {...}
  # format for display in a web page
  $val = htmlesc($val);
  # format for display in a web page table cell
  $val = cellfill($val);
  # remove leading/trailing whitespace
  $val = trim($val);
  # ensure defined value
  $val = define($val);
  # repeat string x number of times
  $val = repeat($val, $iterations);
  # remove leading/trailing quotes
  $val = unquote($val);
  # remove all whitespace
  $val = no_space($val);
  # remove trailing \r and \n, regardless of what
  # the OS considers an end-of-line
  $val = fullchomp($val);
  # or call in void context:
  fullchomp $val;
  # encrypt string using random seed
  $val = randcrypt($val);
  # are these two values equal, where two undefs count as "equal"?
  if (equndef $a, $b) {...}
  # are these two values different, where two undefs count as "equal"?
  if (neundef $a, $b) {...}
  # get a random string of some specified length
  $val = randword(10);


String::Util provides a collection of small, handy utilities for processing strings.


String::Util can be installed with the usual routine:

        perl Makefile.PL
        make test
        make install

You can also just copy Util.pm into the String/ directory of one of your library trees.



Crunches all whitespace in the string down to single spaces. Also removes all leading and trailing whitespace. Undefined input results in undefined output.

hascontent(scalar), nocontent(scalar)

Returns true if the given argument contains something besides whitespace.

This function tests if the given value is defined and, if it is, if that defined value contains something besides whitespace.

An undefined value returns false. An empty string returns false. A value containing nothing but whitespace (spaces, tabs, carriage returns, newlines, backspace) returns false. A string containing any other characers (including zero) returns true.

nocontent() returns the negation of hascontent().


Returns the string with all leading and trailing whitespace removed. Trim on undef returns undef.

So, for example, the following code changes " my string " to "my string":

 $var = " my string  ";
 $var = trim($var);

trim accepts two optional arguments, 'left' and 'right', both of which are true by default. So, to avoid trimming the left side of the string, set the 'left' argument to false:

 $var = trim($var, left=>0);

To avoid trimming the right side, set 'right' to false:

 $var = trim($var, right=>0);


Removes all whitespace characters from the given string.


Formats a string for literal output in HTML. An undefined value is returned as an empty string.

htmlesc is very similar to CGI.pm's escapeHTML. If your script already loads CGI.pm, you may well not need htmlesc. However, there are a few differences. htmlesc changes an undefined value to an empty string, whereas escapeHTML returns undefs as undefs.


Formats a string for literal output in an HTML table cell. Works just like htmlesc except that strings with no content (i.e. are undef or are just whitespace) are returns as  .


Escapes and quotes a string for use in JavaScript. Escapes single quotes and surrounds the string in single quotes. Returns the modified string.


If the given string starts and ends with quotes, removes them. Recognizes single quotes and double quotes. The value must begin and end with same type of quotes or nothing is done to the value. Undef input results in undef output.

option: braces

If the braces option is true, surrounding braces such as [] and {} are also removed.


Takes a single value as input. If the value is defined, it is returned unchanged. If it is not defined, an empty string is returned.

This subroutine is useful for printing when an undef should simply be represented as an empty string. Granted, Perl already treats undefs as empty strings in string context, but this sub makes -w happy. And you ARE using -w, right?

repeat($string, $count)

Returns the given string repeated the given number of times.

randword(length, %options)

Returns a random string of characters. String will not contain any vowels (to avoid distracting dirty words). First argument is the length of the return string.

If the string 'dictionary' is sent instead of an integer, then a word is randomly selected from a dictionary file. By default, the dictionary file is assumed to be at /usr/share/dict/words and the shuf command is used to pull out a word. The hash %String::Util::PATHS sets the paths to the dictionary file and the shuf executable. Modify that hash to change the paths.

option: alpha

If the alpha option is true, only alphabetic characters are returned, no numerals.

option: numerals

If the numerals option is true, only numerals are returned, no alphabetic characters.

option: strip_vowels

This option is true by default. If true, vowels are not included in the returned random string.

equndef($str1, $str2)

Returns true if the two given strings are equal. Also returns true if both are undef. If only one is undef, or if they are both defined but different, returns false.

neundef($str1, $str2)

The opposite of equndef, returns true if the two strings are *not* the same.


Works like chomp, but is a little more thorough about removing \n's and \r's even if they aren't part of the OS's standard end-of-line.

Undefs are returned as undefs.


Crypts the given string, seeding the encryption with a random two character seed.


Returns a string that sorta looks like one or more paragraphs.

option: word_count

Sets how many words should be in the post. By default a random number from 1 to 250 is used.

option: par_odds

Sets the odds of starting a new paragraph after any given word. By default the value is .05, which means paragraphs will have an average about twenty words.

option: par

Sets the string to put at the end or the start and end of a paragraph. Defaults to twonelines for the end of a pargraph.

If this option is a single scalar, that string is added to the end of each paragraph.

To set both the start and end string, use an array reference. The first element should be the string to put at the start of a paragraph, the second should be the string to put at the end of a paragraph.

option: max_length

Sets the maximum length of the returned string, including paragraph delimiters.


Returns the given string represented as the ascii value of each character.

For example, this code:


returns this string:



Takes the output from ords() and returns the string that original created that output.

For example, this command:


returns this string: Hendrix


Compacts contiguous newlines into single newlines. Whitespace between newlines is ignored, so that ntwo newlines separated by whitespace is compacted down to a single newline.


Copyright (c) 2010 by Miko O'Sullivan. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. This software comes with NO WARRANTY of any kind.


Miko O'Sullivan miko@idocs.com


Version 0.10 December 1, 2005

Initial release

Version 0.11 December 22, 2005

This is a non-backwards compatible version.

urldecode, urlencode were removed entirely. All of the subs that used to modify values in place were changed so that they do not do so anymore, except for fullchomp.

See http://www.xray.mpe.mpg.de/mailing-lists/modules/2005-12/msg00112.html for why these changes were made.

Version 1.01 November 7, 2010

Decided it was time to upload five years worth of changes.

Version 1.20 July, 2012

Properly listing prerequisites.

Version 1.21 July 18, 2012

Fixed error in POD. Tightened up code for repet.