44.6 Pattern Matching in case Statements

A case statement (44.5) is good at string pattern matching. Its "wildcard" pattern-matching metacharacters work like the filename wildcards (1.16) in the shell, with a few twists. Here are some examples:

?)

Matches a string with exactly one character like a, 3, !, and so on.

?*)

Matches a string with one or more characters (a non-empty string).

[yY]|[yY][eE][sS])

Matches y, Y or yes, YES, YeS, etc. The | means "or."

/*/*[0-9])

Matches a file pathname, like /xxx/yyy/somedir/file2, that starts with a slash, contains at least one more slash, and ends with a digit.

'What now?')

Matches the pattern What now?. The quotes (8.14) tell the shell to treat the string literally: not to break it at the space and not to treat the ? as a wildcard.

"$msgs")

Matches the contents of the msgs variable. The double quotes let the shell substitute the variable's value; the quotes also protext spaces and other special characters from the shell. For example, if msgs contains first next, then this would match the same string, first next.