Re: Differrent prompt for remote machines

["Bart Schaefer" <schaefer@candle.brasslantern.com>]

On Mar 31, 12:32pm, Zefram wrote:
} Subject: Re: Differrent prompt for remote machines
}
} Dominik Vogt wrote:
} >  Basically it breaks down to detecting if the shell runs on a
} >  local terminal or through a network connection.
} 
} if [[ $TTY == /dev/pts/* || $TTY == /dev/tty[a-z]* ]]; then
} 	PS1='%n@%m> '
} else
} 	PS1='%n> '
} fi

That doesn't work when X11 is involved, because all X terminal emulators
appear to be running "through a network connection" even when they're on
the local machine.

As it turns out, I've been trying to solve a similar problem for another
reason (I'll resist the urge to bore you with details) and came up with
the solution below.

One remaining issue is that if you're on a university timesharing system
or the like, you're probably on /dev/tty[a-z]* even if you're just using
an ancient vt100 in the lab; but even then it should be possible to come
up with a test for "is this shell on a pseudo-terminal".

The `|| ps -lp' is for systems that insist on a leading `-' in the `ps'
options (and therefore probably don't have `w').  Maybe that's overkill.

It should be obvious that this is meant to be a shell function.

---- 8< ---- snip ---- 8< ----
emulate -L zsh
local h ps ppid=$PPID
while (( ppid > 1 ))
do
    ps=("${(f)$(ps lwp$ppid 2>/dev/null || ps -lp$ppid)}")
    h=($=ps[1])
    ps=($=ps[2])
    case "$ps" in
    *sshd*)
	# Shell running from ssh, probably not the local machine
	PS1='%n@%m> '
	break
	;;
    *(xterm|rxvt|dtterm|eterm|gnoterm|emacs)*)
	# Shell running from an emulator, check for local displays
	if [[ -n $SSH_CLIENT ]]
	then
	    # Emulator started from ssh, probably port-forwarding
	    PS1='%n@%m> '
	    break
	elif [[ $DISPLAY = ($HOST*|):* && ${HOSTDISPLAY:-$HOST} = $HOST* ]]
	then
	    # Shell running on a local display (though could be VNC)
	    PS1='%n> '
	    break
	elif [[ -n $DISPLAY ]]
	then
	    # Shell running on a remote display
	    PS1='%n@%m> '
	    break
	else
	    # Probably running inside a text-mode emacs
	fi
	;;
    *login*)
	# Shell running on the local console, or from rlogin or telnet
	if [[ $TTY == /dev/pts/* || $TTY == /dev/tty[A-Za-z]* ]]
	then
	    # Shell running from rlogin or telnet
	    PS1='%n@%m> '
	else
	    # Shell running on local console
	    PS1='%n> '
	fi
	break
	;;
    *)
	# Shell running from su or from some other shell or program
	if [[ -n $SSH_CLIENT ]]
	then
	    # Some ancestor is ssh, probably not local
	    PS1='%n@%m> '
	    break
	fi
	;;
    esac
    # Not enough information yet, climb the process tree
    ppid=${ps[$h[(i)PPID]]:-1}
done
---- 8< ---- snip ---- 8< ----

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Zsh: http://www.zsh.org | PHPerl Project: http://phperl.sourceforge.net