C Shell Shortcuts

filename completion

This feature is activated with the command:

set filec

Filename completion allows you to enter the first character or two of a command or file name and then press the Escape key to have the shell complete the name. This is useful when you have long filenames with many suffixes. If more than one file or directory or command matches the characters you have given, the shell completes as much as possible of the name, and then prompts you with a beep for more information. You can also use the <Ctrl-D> character to select all files or directories that match your given characters.

shell scripts

This feature allows you to create a program that will be executed by the shell. This feature is similar to a programming language in that it has a set syntax and set of instructions, yet it requires no compiler and produces no object file; it is directly executed by the shell. Many administrators use this feature for frequently performed procedures that require some planning and complex execution, such as finding large files and notifying the owners that such files cannot be kept on the system for long periods of time. The shell script programming rules are clearly presented on the csh(1) reference page.

input/output redirection

This feature allows you to direct the output of a command into a file or into another command as input. You can also direct a command to take its input from a file. It is often used as part of a shell script, but is generally used on the command line to string together a series of commands. For example, consider the command line:

ps -ef | grep commandname

The pipe character directs the shell to use the output of the ps command as the input to the grep command. The result is that all instances of the command commandname in the process list are printed on the screen, saving the administrator the effort of searching through the process listing.

job control

This feature allows you to use a single screen (or shell window) to manage several programs running simultaneously. It is most useful for the server administrator who manages the system from a single character-based terminal.

command aliasing

This feature allows you to create aliases for commonly used command strings, saving keystrokes. For example, suppose you frequently give the command:

ls -CF | more

This command line executes the ls command with certain options and ensures that if the output is greater than a screenful it will be stopped until you have read it. However, it would be tedious to type the whole command each time you wanted to see a directory listing in your preferred format. Therefore, you should create an alias. You can alias the above command line to any series of keystrokes you like. You can even alias it to "ls," thus bypassing the standard meaning of the ls command.

When you create the alias, however, be aware that any command that requires one or more arguments, or one such as ls that may or may not receive arguments, must have a provision made in the alias for those arguments. The standard provision made in aliases for possible arguments is the following regular expression:

\!*

The leading backslash escapes the initial meaning of the exclamation point to the shell and passes the exclamation point through to the command line, where it is interpreted by the shell to refer to arguments given on the aliased command line. The asterisk in the expression means that all characters typed in as arguments are to be passed through to the shell. As an example, the line you place in your .cshrc file to create the example alias is:

alias ls 'ls -CF \!* | more'

Then, when you type the command:

ls filename

at your shell prompt, the command is executed as:

ls -CF filename | more

Aliases can be used freely within shell scripts, with filename completion and full use of regular expressions and output redirection.

command history

The shell maintains a log of your past commands given during this login session. You can repeat or edit a previously given command to save keystrokes. The history command shows the numbered log of commands in order. The first command given in your login session is number 1, the second is number 2, and so on. You can set the number of commands the shell remembers in your .cshrc file. To execute the most recent command again, type:

!!

To execute the most recent command beginning with the letter "q," use the command line:

!q

And to execute a command by its number in the history, give the command line:

!n

where n is the number of the previous command you wish to re-execute.