Linux Pocket Guide

Wildcards

Wildcards provide a shorthand for specifying sets of files with similar names. For example, a* means all files whose names begin with lowercase “a”. Wildcards are “expanded” by the shell into the actual set of filenames they match. So if you type:

$ ls a*

the shell first expands a* into the filenames that begin with “a” in your current directory, as if you had typed:

ls aardvark adamantium apple

ls never knows you used a wildcard: it sees only the final list of filenames after the shell expansion.

Wildcard	Meaning
*	Any set of characters except a leading period
?	Any single character
[set]	Any single character in the given set, most commonly a sequence of characters, like [aeiouAEIOU] for all vowels, or a range with a dash, like [A-Z] for all capital letters
[^set] [!set]	Any single character not in the given set (as above)

When using sets, if you want to include a literal dash in the set, put it first or last. To include a literal closing square bracket in the set, put it first. To include a ^ or ! literally, don’t put it first.