Exploring Expect

Length Limits

I have already mentioned that the number of parenthesized expressions in regular expressions is limited to 9. There are two other limits worth mentioning. While it is highly unlikely that you will run into them, describing them may help your peace of mind.

There is a limit on the length of regular expressions. The precise figure depends on the details of a particular regular expression, but 30,000 characters is a safe bet. The length of glob patterns and the strings against which either glob patterns or regular expressions match are limited only to the amount of available memory.