UNIX for Dummies Questions & Answers

I have some basic doubts. Can someone clarify in this forum?
1)if [ "$TERM" = "" ]
then
eval ' tset -s -Q -m ':?hp' '
else
eval ' tset -s -Q '


what does it exactly mean in .profile?
2) what are 'nobody' and 'noaccess' usernames in /etc/passwd file.

3)I am working on a solaris system where there is no specific entry for my username. Then how do the system manage individual login ids?

4) Out of .login , .profile, .cshrc (c shell), .kshrc (k shell) which one gets invoked first after login?

I would be very grateful if someone spends some time in giving me answers to these queries.
Thanks and best regards
Asutosh

1. tset is a program used to set the TERM variable and various stty modes to initialize the users tty environment. I don't like the program and prefer to simply set my TERM variable and use stty as required. The -s makes it output shell commands. The first tset, which is invoked if TERM is not set, will ask the user to enter the terminal type and offer "hp" as a default. The program will then print "TERM=hp ; export TERM" or something very similiar. You can just type the command and observe the results. But this is done inside an eval ` ` construct. Eval is a shell built-in that evaluates its arguments and then executes the resulting command. Type
eval `echo date`
and maybe it will make sense.

2 "nobody" was introduced along with nfs. It's an anomymous user used in nfs security. A process can be given the uid "nobody" which then only allows it to access world readable programs. "noaccess" is similiar, but for files. No process should ever have the uid of noaccess.

3 nis or nis+ perhaps.

4 Now really. Add a line like "echo in .login" to each file and observe the results as you login.

I am going to respond to part 4 of your question specifically.

there are two types of initialization files: user and system. depending on which shell you are using determines which initialization files (both system and user) are executed and in what order. The system initialization files are located in /etc and the user initialization files are locate in the $HOME.

if you are using the c-shell, when you login the /etc/.login file is read first, then the $HOME/.cshrc, then the $HOME/.login. once those files are read, then you get your desktop or whatever.

if you are using the bourne shell or the korn shell, the upon login the /etc/profile is read, then the $HOME/.profile is read. However, the $HOME/.kshrc applies only to the korn shell and is not read automatically. It does not exist by default, thus the user has to create it. in order for it to be read upon login, you have to set the ENV variable in the $HOME/.profile to the following: ENV=$HOME/.kshrc; export ENV. If this variable is set in the $HOME/.profile, this the .kshrc is read immediately after the .profile upon login. Otherwise, the .kshrc IS NOT read without the ENV variable being set.

by the way, if you are using the bash shell (linux and Solaris 8), then the user initialization file in this case would be the $HOME/.bash_profile, which is read after the system initialization file.
hope this helps.

Thank you very much for your reply. My doubts are cleared. Regards
Asutosh