Technical Briefs
ROHAN help Files
shell
The shell is the interface program that reads and interprets your UNIX commands. UNIX was designed so that the shell interface is separate from the main part of the operating system program, so you can modify the interface to make it easier to use. In addition, the shell is also a "programming language", so you can write "scripts" for the shell to follow.
There are six different shells available, each with it's own program used to run it.
Shell Name of Program Bash bash Bourne Shell sh C-Shell csh Korn ksh Tcsh tcsh Zsh zsh The earliest UNIX shell that is still in use is the Bourne shell. The Korn and Bash shells are similar to the Bourne shell, but have several important features which the Bourne shell lacks. These include a history function, job control and aliasing.
The final member of the Bourne Shell Family is Zsh. It is similar to the Bourne, Korn and Bash shells, but it also has more advanced options and has therefore become popular among programmers and advanced UNIX users.
The C-Shell Family includes the C-Shell itself, which was designed to be an alternative to the Bourne shell. The two shells are very similar, but the C-Shell offers many advantages which the Bourne shell doesn't. The C-Shell is the most popular shell in use at universities and in research and is the default shell on ROHAN.
The other member of the C-Shell family is Tcsh. It is similar to the C-Shell, but it offers enhanced features and is often the preferred shell among advanced users.
By default, accounts on ROHAN are setup using the C-Shell. However, it is very easy to change shells at any time by simply typing in the name of the shell you wish to use at the rohan% prompt. This change will only last during your current login session. Once you exit, the shell changes back to it's default setting. If you want to change your default shell, use the chsh command. The syntax is:
When you use chsh to change your shell, the change will not take place until the next time you log in.
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