pregmatch for shell script

*     matches any string of zero or more characters
?     matches any single character
[ ]   matches any single character within the set
[! ]  matches any single character not in the set

These can be combined together to form more advanced patterns:
[Yy]* Matches any string starting with an upper or lower case y.

Use quotes or escape/back-slash the special characters if you wish to pattern match them specifically.