9. Your Working Environment

Your shell is the most important part of your working environment. In DOS, the usual shell is command.com. The shell is what interprets the commands you type on the command line, and thus communicates with the rest of the operating system. You can also write shell scripts, which are like DOS batch files: a series of commands to be run without your intervention.

Two shells come installed with FreeBSD: csh and sh. csh is good for command-line work, but scripts should be written with sh (or bash). You can find out what shell you have by typing echo $SHELL.

The csh shell is okay, but tcsh does everything csh does and more. It allows you to recall commands with the arrow keys and edit them. It has tab-key completion of filenames (csh uses the Esc key), and it lets you switch to the directory you were last in with cd -. It is also much easier to alter your prompt with tcsh. It makes life a lot easier.

Here are the three steps for installing a new shell:

  1. Install the shell as a port or a package, just as you would any other port or package. Use rehash and which tcsh (assuming you are installing tcsh) to make sure it got installed.

  2. As root, edit /etc/shells, adding a line in the file for the new shell, in this case /usr/local/bin/tcsh, and save the file. (Some ports may do this for you.)

  3. Use the chsh command to change your shell to tcsh permanently, or type tcsh at the prompt to change your shell without logging in again.

Note:

It can be dangerous to change root's shell to something other than sh or csh on early versions of FreeBSD and many other versions of UNIX®; you may not have a working shell when the system puts you into single user mode. The solution is to use su -m to become root, which will give you the tcsh as root, because the shell is part of the environment. You can make this permanent by adding it to your .tcshrc file as an alias with:

alias su su -m

When tcsh starts up, it will read the /etc/csh.cshrc and /etc/csh.login files, as does csh. It will also read the .login file in your home directory and the .cshrc file as well, unless you provide a .tcshrc file. This you can do by simply copying .cshrc to .tcshrc.

Now that you have installed tcsh, you can adjust your prompt. You can find the details in the manual page for tcsh, but here is a line to put in your .tcshrc that will tell you how many commands you have typed, what time it is, and what directory you are in. It also produces a > if you are an ordinary user and a # if you are root, but tsch will do that in any case:

set prompt = "%h %t %~ %# "

This should go in the same place as the existing set prompt line if there is one, or under "if($?prompt) then" if not. Comment out the old line; you can always switch back to it if you prefer it. Do not forget the spaces and quotes. You can get the .tcshrc reread by typing source .tcshrc.

You can get a listing of other environmental variables that have been set by typing env at the prompt. The result will show you your default editor, pager, and terminal type, among possibly many others. A useful command if you log in from a remote location and can not run a program because the terminal is not capable is setenv TERM vt100.

All FreeBSD documents are available for download at http://ftp.FreeBSD.org/pub/FreeBSD/doc/

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