Both of these are string deletions. The expression that follows the # is the pattern that is being matched (and deleted), in this case 'a*C'. In other words, the pattern is 'a', followed by 0 or more characters, followed by a 'C'.
The difference between the two examples is that the first does a minimal match (ie, finds the match from the start of the string that is the shortest), while the second does a maximal match (ie, finds the match from the start of the string that is the longest).
Last edited by neonsignal; 02-22-2010 at 02:07 AM.