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HOWTO Documents > Customizing your Computing Environment
Your Account Environment
When you first log into your UNIX account, several default settings will have been chosen for your environment. Most of these settings are stored in "dotfiles" in your home directory, so named because their filenames begin with a period. (These files do not normally appear in directory listings.)
Your account environment includes your shell, special environment variables needed to run software, and, when logging onto a workstation console, your windowing environment.
Your Shell
The default shell you will receive with your account is "tcsh", which is "csh"-compatible and has extensive line-editing capabilities. This "shell" is what you type commands into to do your work. There are two dotfiles which tcsh reads from your home directory to customize itself:
| .tcshrc | read for all new shells | |
| .login | read only for login shells |
Your .login is only read once when you start your first, or "login" shell. Thus you should only put things in here which will affect your entire session, such as terminal (stty) settings, or things which you only want to run once each time you login. You should probably at least keep the default .login given to you, which runs the program "ccsnews" to display important announcements when you login.
Your .tcshrc is read for every shell that is created, which
includes "subshells" that you run from within an editor, or shells
that you invoke on a remote machine via rsh. Thus you should
place here settings which you want to affect every shell, such as how
many commands to remember in the history buffer, or what you want your
prompt to look like. Note that some settings only make sense for
interactive shells; many settings will be unnecessary for rsh
or scripts. You can detect an interactive shell from a non interactive
one by testing for the $prompt variable, like this:
if ($?prompt) then
bindkey ^W backward-delete-word
set prompt = "$USER@$HOSTNAME> "
...
endif
Don't feel intimidated if none of this makes sense to you. As you use your account you'll gradually learn what things you may want to change in these files and why.
You may wish to look at the default .tcshrc and .login files found in /ccs/etc/dotfiles as a guide to customizing your own.
Other shells are available besides "tcsh", including "bash" and "zsh". You can change your shell by using the chsh command. (You will have to logout and login again to use the new shell.)
Your PATH and .software
There is one setting for your account which is of particular importance; that is your "PATH" environment variable. This variable contains a list of directories which your shell will search when looking for the name of a program or command that you typed. The way that your PATH variable is set on our systems is different from most computing environments.
One dotfile in your home directory, ".software", is used to set both your PATH and MANPATH variables (as well as possibly some other variables necessary to use certain software). You should look at the default .software provided to you to learn how to change it. Normally you should not need to modify the default setting given to you. However, if you prefer an alternate configuration, or if you have special directories with executable commands you want to have in your "PATH", modifying your .software file is not difficult. Read the software manual page (type: man software) for specific details.
If you want to add a special directory to your path, add this to your .software file:
PATH=/some/special/bin/dir
Other examples of .software files can be found in
/ccs/examples/dotfiles
If you modify your .software file, the changes you make will
not take effect until the next time you login, or until you type
‘resoft’.
Your Windowing Environment
When you login to a workstation console, you are placed in a windowing environment called X Windows. There are several ways in which you can customize your X environment, by modifying one or more of the following files:
| .xsession | login session script | |
| .xclients | custom clients | |
| .mwmrc | Motif WM customization | |
| .twmrc | Tab WM customization | |
| .vtwmrc | VTab WM customization | |
| .Xdefaults | general X settings |
Some of these files may already exist in your home directory. You may wish to look at the default dotfiles located in "/ccs/etc/dotfiles", or other samples in "/ccs/examples/dotfiles".
Resetting your Environment
It may happen that you accidentally destroy your dotfiles to the point
that you have a nonfunctional environment. If this happens, you can
restore the default environment by running the following command:
/ccs/bin/proto me
This will replace a subset of your dotfiles with some default
ones. You will need to logout and back in again to see the change.
You can restore your old environment again by typing:
proto undo
Or, if you are content to keep the new default environment given to
you:
proto clean
If you have other problems, or questions about your environment, please do not hesitate to send mail to systems@ccs.neu.edu describing in detail your question or problem.