What follows assumes a rudimentary understanding of some basic UNIX concepts and terminology. If you are new to UNIX, you may want to acquire a book to help you get started. Check this Concise Guide to UNIX Books for suggestions, or ask a UNIX-savvy colleague for a recommendation. If you are new to UNIX at SLAC, you should also glance through some of the information in SCS's Introduction to UNIX at SLAC.
The UNIX operating system is case sensitive. In the following examples, UNIX commands are written like this and must be typed exactly as written.
tcsh
If you do not already have an account on the Central UNIX cluster, your first step is to get one.
SCS will give you a home directory named
/u/ey/
<user>,
where <user> is your username,
on one of the file servers.
(At present, home directories are set up
on an NFS server,
but in the near future the default will probably change to
AFS.)
The way in which your UNIX environment gets initialized when you login
depends on your login shell".
At SLAC, the default login shell is now tcsh
which is also the recommended shell for SLD users.
In the recent past, however,
SLAC's default login shell was csh
,
which provides a subset of the facilities available in tcsh
.
The SLD environment should be compatible with either of these shells,
but if you switch to one of the other UNIX shells, you're on your own.
To check which shell you're currently running type
ljm$hebe $ echo $SHELL
If the result is something like
/bin/cshor
/bin/tcshor
/usr/local/bin/tcshyou're running an SLD-compatible shell; nevertheless, if you're running
csh
we recommend that you swicht to its more user-friendly cousin,
tcsh
.
Every time a csh
or tcsh
shell begins,
it executes a script named .cshrc
in your home directory;
then, if the shell is a login shell,
it also executes the script named .login
, also in your home directory.
ljm@hebe $ cd $HOME ljm@hebe $ mv .cshrc .cshrc-SCS ljm@hebe $ mv .login .login-SCS ljm@hebe $ cp /afs/slac/g/sld/etc/Newuser/sample.cshrc .cshrc ljm@hebe $ cp /afs/slac/g/sld/etc/Newuser/sample.login .login
.cshrc
or .login
scripts,
you should use an editor to merge them with
the sample scripts in the example above.
/afs/slac/g/sld/etc/Newuser/insert.cshrc /afs/slac/g/sld/etc/Newuser/insert.loginwhich contain the minimal additions needed in your
.cshrc
and .login
scripts
to setup the SLD environment.
Please note that these two "insert" files are not complete in themselves
and should not replace your existing scripts.
The "sample" scripts are also inteneded as repositories of useful enhancements for your UNIX environment. You may want to refer to them from time to time to review any new suggestions.
Once you've modified your .cshrc
and .login
scripts
the SLD environment should be properly setup the next time you login.
If you'd like to set it up immediately, without logging off,
you must source (not simply execute) these scripts:
ljm@hebe $ cd $HOME ljm@hebe $ source .cshrc ljm@hebe $ source .login
To check that the SLD environment has, indeed, been setup, enter the command
ljm@hebe $ echo $SLDROOT
The result should be something like
/afs/slac.stanford.edu/g/sld
If this is the first time you have logged in to your new UNIX account you should change your password. It is particularly important to choose a good password in UNIX, which is a very open environment and thus tends to attract many attacks on its security.
Once you've selected a good string to use as a password,
enter the yppasswd
command
(not the passwd
command)
and respond to the prompts as shown below
(some local UNIX gurus claim that it is safer to do this
while logged in to a Sun host, such as unixhub
,
rather than an RS/6000):
ljm@unixhub $ yppasswd ljm Changing NIS password for ljm on afsdb1. Old password: New password: Retype new password: NIS entry changed on afsdb1
Note that your old and new passwords will not appear on the screen.
Password changes may take up to six hours to go into effect, so don't forget your old one until you've successfully used the new one to login.
tcsh
The tcsh
shell program offers
a number of advantages over csh
.
One of the most important for users familiar with VMS
is a similar command line editing facility.
To make tcsh
your login shell,
enter the ypchsh
command (only available on Sun hosts)
and respond to the prompts as follows:
ljm@unixhub $ ypchsh ljm Changing NIS login shell for ljm on afsdb1. Old shell: /bin/csh New shell: /usr/local/bin/tcsh Password: NIS entry changed on afsdb1
You must also make a change in your .cshrc
script.
Using an editor, locate the line that looks like
eval `/usr/local/bin/environ /bin/csh ...`and change the
/bin/csh/
to /usr/local/bin/tcsh/
.
As with passwords, changes to your login shell may take up to six hours to go into effect.
A staging system is available to simplify access to large Unix data files. A set of utilities are provided to copy such files from disk to tape and back again.
A writeup on this Unix Staging System has been adapted from Charlie Young's E143 documentation.
The usage policy is for people to create a directory on the disk with the same name as their account.
These files can be copied directly from VMS via NFS, using the NFS addresses for the SLACVX user and scratch disks of /nfs/slacvx/sld_usr0/ and /nfs/slacvx/sld_tmp0/scratch/, followed by your own directories.
This disk is cleaned every morning, erasing files older than 5 days. The erasure policy is written up in a README file on the disk.