Hi Experts,
Need your help in understanding the commands to setup the environment variables in hp-ux.
Beleive need to use either set,setenv or export.
I am confused between above three options, when to use which option?
On command line, I have tried both set and setenv but couldn't able to set the environment variables. However with export it was working fine.
With standard shell or compatible shell (/etc/passwd has /bin/sh or /bin/ksh or /bin/bash or /bin/zsh) it uses
var=value
for a shell-internal variable. And
export var
to promote it to environment. Environment is inherited by the commands that the shell invokes.
The standard shell and compatibles process such commands in $HOME/.profile at a login.
If the shell in /etc/passwd is /bin/csh or /bin/tcsh then the syntax is different:
set var=value
for shell-internal, and
setenv var=value
for environment. There is some confusion if you do both with the same variable. By convention you should do
set var=value
setenv VAR=value
I.e. lowercase of internal variables and uppercase for environment variables.
The csh and tcsh process such commands in $HOME/.login at a login.
Usually the SHELL environment variable is set from the one in /etc/passwd:
echo $SHELL
You did not say what version of HP-UX you are working on...
Till 11.23 ( after I dont know...) the default user shell was ksh , so you would use either .profile or .kshrc in your home directory, for root user its a little different...
I will add to previous post that you can in .kshrc and even in .profile now ( since 11.00 ? ) use also this syntax:
export VAR=value
A correction: ksh does not take .kshrc. It takes an environment variable ENV.
You can of course put the following into .profile
#ksh takes this startup file:
ENV=$HOME/.kshrc; export ENV
Thanks for the correcting me, was so obvious I zapped the magic line you need in .profile ...
There is a good reason to use a .kshrc if you use/have heavy customisation.:
To be sure no one has a corrupt environment when upgrading/patching OS if a new .profile is provided in the upgrade, it will be used as default for all users, thus avoiding extra most probable useless calls to internal support team... and as MadeInGermany flagged, the only thing we check here is that the magic line is present , if not will be added to the default...
Things get more complicated when using X server on PC with ssh and have an heterogenous environment with many flavours of UX/linux...
If ENV is found in the environment when an interactive ksh is invoked, then parameter expansion, command substitution, and arithmetic substitution are performed on the value of $ENV to generate the pathname of a script that will be executed before the first prompt is issued. If ENV is not found in the environment when an interactive ksh is invoked and there is a file named .kshrc in your login directory, that file will be executed before the first prompt is issued.
Depending on how ksh is configured on your system, it may also look for /etc/ksh/.kshrc . On systems that are configured to use this file, you can skip executing it by setting ENV to a string starting with /./ or ././ (such as /.$HOME/.kshrc to execute only $HOME/.kshrc or /./dev/null to avoid executing either of those files).
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The HP-UX 11i man page says:
ENV If this parameter is set, parameter substitution
is performed on the value to generate the path
name of the script to be executed when the shell
is invoked (see Invoking ksh below). This file is
typically used for alias and function definitions.
I does not mention .kshrc. And practical tests prove that only the ENV is implemented, and it works in both interactive and non-interactive shells.