C Shell Scripting/Setup
Setting up your Environment 
The C shell executable file is called csh. Most Unix systems have this shell installed except if the system just has the essentials installed. C shell is not a POSIX shell so if the system has only one shell is would most likely be a Bourne shell. Easiest way to check if you have C shell is to run the which command and see if it returns the path to the csh file.
$ which csh /bin/csh
The result will most likely be
/bin/csh which is the standard location. If the command doesn't print out a path the executable is not installed and you will have to download and installed the executable.
Figuring out the version of the C shell should also be done. If the output of this command indicates that your shell is an old version, upgrading to a newer version may save some headaches later.
Simply run the command with the
$ csh --version tcsh 6.14.00 (Astron) 2005-03-25 (i386-apple-darwin) options wide,nls,dl,al,kan,sm,rh,color,filec
For example, Mac OS X 10.5.7 displays
tcsh 6.14.00. It should not be surprising to find the tcsh executable masquerading as the older csh executable since its is backward compatible.
Linux has many different methods to install applications. One way is the apt-get command.
$ sudo apt-get install csh
Mac OS X 
Mac OS X should always have csh installed. But you may want to get an editor such as TextMate to color the syntax.