Regular expressions can vary from simple to WTF. Usually they tend toward the latter. What most don't realized, or are too lazy to use, is that regular expressions can be made to include friendly whitespace and comments. CFEngine is no exception.
Continue reading Build better regular expressions in CFEngine...
Although similar to Perl, PCRE has some syntax that can be difficult to remember. When I'm working with CFEngine I often have to look it up. Here is a cheat-sheet to save time.
| Alphabetic | [:alpha:] |
| Alphanumeric | [:alnum:] |
| Control characters | [:cntrl:] |
| Hex numbers | [:xdigit:] |
| Lowercase | [:lower:] |
| Nonespace characters | [:graph:] |
| Numbers | [:digit:] |
| Printable | [:print:] |
| Punctuation | [:punct:] |
| Tab or space | [:blank:] |
| Uppercase | [:upper:] |
| White space | [:space:] |