Regular expressions:

A regular expression is a concise way of expressing any pattern of characters.

You construct a regular expression by combining ordinary characters with one or more metacharacters: characters that have special meaning.

The following characters can be used to create regular expressions for searching.

• c any non-special character represents itself
• \\c turns off the meaning of any special character
• ^ beginning of a line
• $ end of a line
• . matches any single character except a newline
• [...] matches any character that is in the enclosed list of characters
• [^...] matches any character that is not in the enclosed list of characters
• [c1-c2] matches any character alpabetically between character c1 and c2, inclusive
• * matches the longest possible string that matches the preceding character or construct

Examples:

To look up only Onatrio callsigns with two character suffixes, you would use 'v.3..$'

Suppose heard a members VE3 callsign but couldn't make the suffix but were sure it started with 'T', 'V' or 'C', use the search string 've3[tvc]..'