Editing C shell (section)

==== Wildcarding ====

The C shell, like all Unix shells, treats any command-line argument that contains wildcard characters as a pattern and replaces it with the list of all the filenames that match (see [[globbing]]).

*<code>*</code> matches any number of characters.
*<code>?</code> matches any single character.
*<code>[</code>...<code>]</code> matches any of the characters inside the square brackets.  Ranges are allowed, using the hyphen.
*<code>[^</code>...<code>]</code> matches any character ''not'' in the set.

The C shell also introduced several notational conveniences (sometimes known as [[extended globbing]]), since copied by other Unix shells.

*<code>abc{def,ghi}</code> is [[Alternation (string expansion)|alternation]] (aka [[Bash (Unix shell)#Brace expansion|brace expansion]]) and expands to ''abcdef'' ''abcghi''.
*<code>~</code> means the current user's home directory.
*<code>~user</code> means ''user'''s home directory.

Multiple directory-level wildcards, e.g., "<code>*/*.c</code>", are supported.

Since version 6.17.01, recursive wildcarding à la [[Z shell|zsh]] (e.g. "<code>**/*.c</code>" or "<code>***/*.html</code>") is also supported with the <code>globstar</code> option.

Giving the shell the responsibility for interpreting wildcards was an important decision on Unix.  It meant that wildcards would work with every command, and always in the same way.  However, the decision relied on Unix's ability to pass long argument lists efficiently through the [[exec (system call)|exec]] system call that csh uses to execute commands.  By contrast, on [[Windows]], wildcard interpretation is conventionally performed by each application. This is a legacy of MS-DOS, which only allowed a 128-byte command line to be passed to an application, making wildcarding by the DOS command prompt impractical. Although modern [[Microsoft Windows|Windows]] can pass command lines of up to roughly 32K [[Unicode]] characters, the burden for wildcard interpretation remains with the application.