Path: utzoo!mnetor!uunet!husc6!bbn!diamond.bbn.com!mlandau
From: mlandau@bbn.com (Matt Landau)
Newsgroups: comp.unix.wizards
Subject: Re: How to have PS1 evaluated after each "cd"
Message-ID: <10456@jade.BBN.COM>
Date: 31 Dec 87 20:29:00 GMT
References: <574@ambush.UUCP> <1876@netsys.UUCP> <1374@bucsb.UUCP>
Reply-To: mlandau@bbn.com (Matt Landau)
Organization: BBN Laboratories Incorporated, Cambridge, MA
Lines: 27
Summary: In tcsh you can use precmd

In comp.unix.wizards (<1374@bucsb.UUCP>), eap@bucsb.UUCP (Eric Pearce) writes:
>I've been using this for quite a while under csh/tcsh (I did not write
>it myself)
>
> [Demo of using alias to change prompt on cd, pushd, etc.]

Well, if you can run tcsh, you can use the precmd alias to have your prompt
set each time it is printed.  I use to following on my Suns:

    if ($TERM == "sun" && `tty` != "/dev/console" && ! $?EMACSEDIT_TTY) then
      set   prompt = "%S$prompt%s"
      alias precmd  echo -n '^[]l  ${root}${HOST}:${cwd}^[\\ '
    else if ($TERM =~ xterm* && ! $?EMACSEDIT_TTY) then
      alias precmd  echo -n '^[]l  ${root}${HOST}:${cwd}^[ '
    endif

$HOST and $cwd are maintained by tcsh, and $root is set by a simple test 
to "#" if I have superuser privileges in this shell.  The escape sequences
set the window banner for each shelltool or xterm window so that it contains
the hostname and working directory, in a form like "diamond:/usr/local/src".

Since this precmd uses only shell variables and builtins, it's acutally fast 
enough that you can reset the prompt after every command without feeling any 
performance penalty.
--
 Matt Landau			Waiting for a flash of enlightenment
 mlandau@bbn.com			  in all this blood and thunder