1.0 The Shell

In the Unix world a "shell" is a command interpreter. Basically, commands are typed into a shell and those commands are passed to the computer to be processed. On many Unix systems you are given a choice as to which shell you would like to use.

The oldest shell being the Bourne shell (sh), is most widely available and is very good for writing shell scripts. The Korn shell (ksh), which was developed by At&T is mostly found on System V-based Unix systems. The C shell (csh) is a popular shell which came from Berkeley Unix and is very good for interactive use.

The tcsh is a close cousin of the csh. Most of what you know about the csh can be applied to the tcsh. Some advantages tcsh offers over the other shells mentioned are: command-line editing, better word completion facilities, spelling correction, quick access to previously typed commands, rm * detection to prevent disastrous removals, quicker bug fixes and better standardization (many vendors make small modifications to their version of csh, making its behavior vary from vendor to vendor).

The tcsh is a shell that is not yet considered a standard. Most vendors do not ship the tcsh as part of their operating system. It is however freely available via the internet and has been installed on most Unix systems here at Wesleyan. However, your account on the Mail server has been setup with a restricted shell. This restricted account puts limits on what you will be able to do. When you log into the Mail sevrer you will be presented with a menu of choices to choose from. This is not the case on Condor. Each user can choose to work with any of the shells mentioned above. Accounts on Condor have been setup with tsch as the default.

A few tips when using the tcsh:

  • -Use the tab key to complete long file names.
  • -Use the up and down arrows for command line history.
  • -cd ~username (go to home dir).
  • -man tcsh (view man pages for further detailed descriptions).

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