Bash script won't run because hardware won't produce display

UNIX for Beginners Q & A
1

Can anyone offer any advice on how to modify the script below to work on a new system we have, that has no graphics capability? We admin the system through a serial RAS device. I've tried running the below script through the RAS and through an ssh -X session. It failed with something like "GTK unable to produce display". Python scripts however do produce menus and such on screen and I don't understand the difference. Any help/advice is greatly appreciated. Thank you.

This script is supposed to produce a text box on screen, that our installers enter a 4 digit code on. That code is checked for validity and if it is, the script completes. I have several other scripts just like this one, all with the same problem. Is is zenity????

#!/bin/bash

VER=`zenity --entry --text "Please enter the ACG pgm number:" --title "Version Entry"`

if [ -z "$VER" ]; then
	echo "ERROR: Version entry was not provided."
	exit 1
fi

IS_OK=`echo $VER | egrep "[0-9]{4}"`

if [ -z "$IS_OK" ]; then
	zenity --question --text "'$VER' does not appear to be a
valid version string.

Continue anyway?"
	if [ $? -ne 0 ]; then
		echo "ERROR: Invalid version entry."
		exit 1
	fi
fi

echo $VER > /etc/acg-oe-pgm
2

Hi,

Yes, the issue here is most likely to be zenity , as you say. zenity is a utility for displaying dialog boxes in an X Windows graphical environment. If you're running this server headless (i.e. you have no monitor connected and are interacting with it purely over a serial link) then zenity isn't going to work. Your best bet would be to switch out zenity for another text-only utility such as dialog , which can display interactive full-screen text mode dialog boxes to query the user for information. That should work in any terminal session regardless of whether the script was being started in an xterm running in X11, on a text mode virtual console, or over a serial link. If you check out the man page for dialog it'll give you a description of how it works, but it shouldn't be too hard to re-work your script to use one rather than the other.

2 Likes
3

The following shell script emulates zenity on a console device.

#!/bin/bash

if [ -n "$DISPLAY" ] && xdpyinfo >/dev/null 2>&1
then
  graphics=1
else
  graphics=
fi

# a wrapper for zenity that does console I/O if no graphics
dialog(){
  if [ -n "$graphics" ]
  then
    zenity "$@"
    return
  fi
  do_text= text= do_yes_exit=
  for arg
  do
    if [ -n "$do_text" ]
    then
      text=$arg
      do_text=
    else
      case $arg in
      (--text) do_text=1;;
      (--question) do_yes_exit=1;;
      esac
    fi
  done
  read -p "$text: " input
  if [ -z "$do_yes_exit" ]
  then
    echo "$input"
    return
  fi
  case $input in
  ([Yy]*) return 0;;
  esac
  return 1
}

VER=$(
  dialog --entry --text "Please enter the ACG pgm number:" --title "Version Entry"
)

if [ -z "$VER" ]; then
  echo "ERROR: Version entry was not provided."
  exit 1
fi

case $VER in
([0-9][0-9][0-9][0-9])
;;
(*)
  dialog --question --text "'$VER' does not appear to be a
valid version string.

Continue anyway?"
;;
esac

if [ $? -ne 0 ]
then
  echo "ERROR: Invalid version entry."
  exit 1
fi

echo "$VER" > /etc/acg-oe-pgm
1 Like
4

Just wanted to take a moment and thank you all for your help. It's greatly appreciated. Cheers~