On Tue, Feb 21, 2012 at 7:32 AM, Sam Kreimeyer <skreimey@gmail.com> wrote:

Here's a pdf of a quick guide to regular expressions
http://www.addedbytes.com/download/regular-expressions-cheat-sheet-v1/pdf/

Basically, it's a format for defining search patterns that supports special meanings for certain characters. For instance:

a - finds any string like "a"
a. - finds any string like "a" plus any other character except a new line (matches "aa", "ab", "ac", etc)
a.* - finds any string like "a" plus zero or more characters except a new line (matches "aa", "abcdefghijk")
Other special characters can further modify this behavior.

So here's an explanation of the earlier command.

's/\.JPG$/.jpg/' *.JPG

Basic search and replace format s/[string we search for]/[string to replace matches with]/

"\.JPG$" - Because "." is special, we escape it with "\" to keep the regex from interpreting it, so the "." will be treated literally. "JPG" is what we're looking for. Placing a "$" at the end of the string tells the regex to match the string only at the end of the strings you're searching. This means that you will match "example.JPG" but not "JPG.example".

".jpg" - This is our replacement string. This is what goes in the place of every match we find.

"*.JPG" - while this isn't part of the regex, "*" is a wildcard (can be substituted for any number of characters).

Hope that helps!

---------------------------------------------------
PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us
To subscribe, unsubscribe, or to change your mail settings:
http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss