Regular Expressions

Bulk Rename Utility

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Regular Expressions

The applications support powerful Regular Expression processing. This allows you to enter a flexible Match expression, and a flexible Replacement expression, and the program will generate the appropriate name using these expressions. For example, you can use RegExp strings to swap two words in a filename, or remove numbers, or apply fixed formatting.

A full description of Regular Expressions is beyond the scope of this help file, but a wide range of resources is available on the internet (e.g. groups.google.com). However, the syntax supported by this program is the same as that offered by PERL 5. The precise implementation is via the PCRE Library, and (at the time of writing) full notes on the Perl Regular Expression syntax can be found here.

A summary of the syntax is:

Character	Usage
*	Matches the previous character zero or more times
+	Matches the previous character one or more times
?	Matches the previous character zero or one times
.	Matches any single character except the newline
^	Matches the start of the input
$	Matches the end of the input
x\|y	Matches either first or second character listed
(pattern)	Matches pattern
{number}	Matches exactly number times
{number,}	Matches number, or more, times (note comma)
{num1, num2}	Matches at least num1 and at most num2 times
[abc]	Matches any character listed between the [ ]
[^abc]	Matches all characters except those listed between the [ ]
[a-e]	Matches any characters in the specified range (a,b,c,d,e)
[^K-Q]	Matches all characters except in the specified range
\	Signifies that the next character is special or a literal.
\b	Matches only on a word boundary
\B	Matches only inside a word
\f	Matches only on a form feed character
\n	Matches only on a new line
\r	Matches only on a carriage return
\s	Matches only on a blank space
\S	Matches only on nonblank spaces
\t	Matches only on a tab
\d	Matches any digit

Replacements are usually performed on the basis of "components, and these are defined using \ notation, e.g. \1 matches the first element, \2 matches the second

Example Regular Expression:

Match: (Louis Armstrong)(.\[0-9].)([A-Za-z ]*)

Replace: \1 \3

A more detailed working example can be found here.

You can choose whether or not to pass the filename extension to the Regular Expression engine, or just the filename itself.

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