How to set the command(s) that get run before every single prompt?

Question

I used to know this but I forgot: I want to execute a command or a couple of commands before every single prompt. When I am in our PROD box, I want a big fat reminder above every prompt that says * YOU ARE IN PROD * and maybe another thing or two. Currently, I think that is how mail is checked but I can't remember how that configuration is set.

Using ksh and Solaris 5.10

Any idea?

Thanks

Answer 1

I'd simply put it into /etc/profile, or /etc/issue. Sometimes displaying the contents of the issue file is turned off, but I'd still think it's a good reminder.

Changing the contents of the $PS1 variable is ok, I guess, you might want to still print some warnings /etc/profile. Since it's a production system, It's ok to edit those files, since here, you want lasting changes in the system. (Normally, I'd advise against changing those files and using user files instead.)

Answer 2

In ksh, $PS1 is subject to command substitution and parameter expansion, so you can do things like:

function mywarning {
  tput setaf 1; tput bold
  date "+it's %T, please remember it's a production system"
  tput sgr0
}

PS1='$(mywarning)# '