Filename Expansion

One powerful characteristic of the UNIX system is filename expansion. That enables to work with files collectively. The set of filename-matching characters is represented through wildcards. A Wildcards permit several files to be manipulated at the similar time using a single command.  A Wildcards are a type of shorthand which permits same files to be specified without having to type several names.

There are three categories of UNIX wildcards: *, ?, []. A shell expands these wildcards, substitutes a set of valid filenames and these filenames are then provided to the respective commands.

*          This will match zero or further characters

?          This will match exactly one character

[ ]         This will match any one of the characters in the given range