UNIX for Dummies Questions & Answers

Hello, can anyone explain me please what do those lines do ?

From file .login

1) set history=40
2) setenv MACH `uname -s`
3) source /etc/login
4) source ~/$MACH/.login

From file .cshrc

1) if ( ! $?prompt) exit 0

The .cshrc example is checking whether you are in background (and therefore with no terminal context) and avoiding executing subsequent commands which need a terminal.

The lines from ".login" are easy to look up.

history remembers the most recent events done on the command line set history=40

---------- Post updated at 07:14 PM ---------- Previous update was at 07:08 PM ----------

For actions for the user to be performed only once upon login, you have a line "source /etc/login" at the top of every user's $HOME/.login

Thank you all for Your help, I almost got everything expect one :

"setenv MACH `uname -s`"

The setenv command alters the environment (standard settings) of the program. The environment contains parameters for the commands that the user does not want to specify every time a command is used.

For example, if you want to define a short name for a particular directory:

Code:

setenv PS $HOME/docs/postscript

allows you subsequently to refer to the subdirectory called postscript as $PS

uname (short for unix name) is a software program in Unix and Unix-like computer operating systems that prints the name, version and other details about the current machine and the operating system running on it.

This returns basic machine Operating System (e.g. HP-UX). Try it on your system(s).
Line 4) then uses the value of $MACH to "source" a suitable additional ".login" file for this Operating System.
It's a clever way to have a central common ".login" file which you can proliferate to multiple accounts on multiple computers.