String::Util -- String processing utility functions


String::Util provides a collection of small, handy functions for processing strings in various ways.


  cpanm String::Util


No functions are exported by default, they must be specified:

  use String::Util qw(trim eqq contains)

alternately you can use :all to export all of the functions

  use String::Util qw(:all)



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

Note: crunch() is an alias to this function. It is considered deprecated. It may be removed in future versions.

  $var = collapse("  Hello     world!    "); # "Hello world!"

hascontent($scalar), nocontent($scalar)

hascontent() returns true if the given argument is defined and 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 characters (including zero) returns true.

nocontent() returns the negation of hascontent().

  $var = hascontent("");  # False
  $var = hascontent(" "); # False
  $var = hascontent("a"); # True

  $var = nocontent("");   # True
  $var = nocontent("a");  # False

trim($string), ltrim($string), rtrim($string)

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

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

ltrim() trims leading whitespace only.

rtrim() trims trailing whitespace only.


Removes all whitespace characters from the given string. This includes spaces between words.

  $var = nospace("  Hello World!   "); # "HelloWorld!"


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

htmlesc() is very similar to's escapeHTML. However, there are a few differences. htmlesc() changes an undefined value to an empty string, whereas escapeHTML() returns undefs as undefs.


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. Some examples and what they return:

  unquote(q|'Hendrix'|);   # Hendrix
  unquote(q|"Hendrix"|);   # Hendrix
  unquote(q|Hendrix|);     # Hendrix
  unquote(q|"Hendrix'|);   # "Hendrix'
  unquote(q|O'Sullivan|);  # O'Sullivan

option: braces

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

  unquote(q|[Janis]|, braces=>1);  # Janis
  unquote(q|{Janis}|, braces=>1);  # Janis
  unquote(q|(Janis)|, braces=>1);  # Janis

repeat($string, $count)

Returns the given string repeated the given number of times. The following command outputs "Fred" three times:

  print repeat('Fred', 3), "\n";

Note that repeat() was created a long time based on a misunderstanding of how the perl operator 'x' works. The following command using 'x' would perform exactly the same as the above command.

  print 'Fred' x 3, "\n";

Use whichever you prefer.

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. So this code:

  foreach my $idx (1..3) {
      print randword(4), "\n";

would output something like this:


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. So this code:

  foreach my $idx (1..3) {
      print randword('dictionary'), "\n";

would output something like this:


option: alpha

If the alpha option is true, only alphabetic characters are returned, no numerals. For example, this code:

  foreach my $idx (1..3) {
      print randword(4, alpha=>1), "\n";

would output something like this:


option: numerals

If the numerals option is true, only numerals are returned, no alphabetic characters. So this code:

  foreach my $idx (1..3) {
      print randword(4, numerals=>1), "\n";

would output something like this:


option: strip_vowels

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

  foreach my $idx (1..3) {
      print randword(4, strip_vowels=>1), "\n";

would output something like this:


eqq($scalar1, $scalar2)

Returns true if the two given values are equal. Also returns true if both are undef. If only one is undef, or if they are both defined but different, returns false. Here are some examples and what they return.

  $var = eqq('x', 'x');     # True
  $var = eqq('x', undef);   # False
  $var = eqq(undef, undef); # True

Note: equndef() is an alias to this function. It is considered deprecated. It may be removed in future versions.

neqq($scalar1, $scalar2)

The opposite of neqq, returns true if the two values are *not* the same. Here are some examples and what they return.

  $var = neqq('x', 'x');     # False
  $var = neqq('x', undef);   # True
  $var = neqq(undef, undef); # False

Note: neundef() is an alias to this function. It is considered deprecated. It may be removed in future versions.


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

  $var = ords('Hendrix'); # {72}{101}{110}{100}{114}{105}{120}


  • convert_spaces=>[true|false]

    If convert_spaces is true (which is the default) then spaces are converted to their matching ord values. So, for example, this code:

      $var = ords('a b', convert_spaces=>1); # {97}{32}{98}

    This code returns the same thing:

      $var = ords('a b');                    # {97}{32}{98}

    If convert_spaces is false, then spaces are just returned as spaces. So this code:

      ords('a b', convert_spaces=>0);        # {97} {98}
  • alpha_nums

    If the alpha_nums option is false, then characters 0-9, a-z, and A-Z are not converted. For example, this code:

      $var = ords('a=b', alpha_nums=>0); # a{61}b


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

  $var = deords('{72}{101}{110}{100}{114}{105}{120}'); # 'Hendrix'

contains($string, $substring)

Checks if the string contains substring

  $var = contains("Hello world", "Hello");   # true
  $var = contains("Hello world", "llo wor"); # true
  $var = contains("Hello world", "QQQ");     # false

  # Also works with grep
  @arr = grep { contains("cat") } @input;

startswith($string, $substring)

Checks if the string starts with the characters in substring

  $var = startwith("Hello world", "Hello"); # true
  $var = startwith("Hello world", "H");     # true
  $var = startwith("Hello world", "Q");     # false

  # Also works with grep
  @arr = grep { startswith("X") } @input;

endswith($string, $substring)

Checks if the string ends with the characters in substring

  $var = endswith("Hello world", "world");   # true
  $var = endswith("Hello world", "d");       # true
  $var = endswith("Hello world", "QQQ");     # false

  # Also works with grep
  @arr = grep { endswith("z") } @input;


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

  $var = crunchlines("x\n\n\nx"); # "x\nx";

sanitize($string, $separator = "_")

Sanitize all non alpha-numeric characters in a string to underscores. This is useful to take a URL, or filename, or text description and know you can use it safely in a URL or a filename.

Note: This will remove any trailing or leading '_' on the string

  $var = sanitize("") # http_www_google_com
  $var = sanitize("foo_bar()";              # foo_bar
  $var = sanitize("/path/to/file.txt");     # path_to_file_txt
  $var = sanitize("Big yellow bird!", "."); # Big.yellow.bird

file_get_contents($string, $boolean)

Read an entire file from disk into a string. Returns undef if the file cannot be read for any reason. Can also return the file as an array of lines.

  $str   = file_get_contents("/tmp/file.txt");    # Return a string
  @lines = file_get_contents("/tmp/file.txt", 1); # Return an array


Copyright (c) 2012-2016 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 <>

Scott Baker <>