Just a small finger exercise …

#!/usr/bin/env python3

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk
import os
import sys

class GUI:
    def __init__(self):
        self.window = Gtk.Window()
        self.window.connect('destroy', Gtk.main_quit)
        self.textview = Gtk.TextView()
        self.textview.connect("drag-data-received", self.on_drag)
        self.window.add(self.textview)
        self.window.show_all()
        self.buffer = self.textview.get_buffer()

    def on_drag(
        self,
        widget,
        drag_context,
        x,
        y,
        data,
        info,
        time
    ):
        text = data.get_text()
        print("DEBUG: text = %s" % text)
        self.buffer.set_text("")

def main():
    app = GUI()
    Gtk.main()

if __name__ == "__main__":
    sys.exit(main())

Introduction

In this article i try to find out, if Bourne Shell scripts are runnable in Bourne Again Shell without modification. If not, i advice on how to modify the code so that it runs on both Shells.

An interpreter for some variant of Bourne Shell is available as an executable /bin/sh on most Linux and UNIX systems. Writing Bourne Shell script has the possible advantage that such a script can work on all these systems with no changes to the code; be it Linux, AIX, FreeBSD, initramfs or a string passed to a C library call system(3), expressions such as

• echo hello | wc
• my_pid=$$

or

• exit 1

would always work.

Recently, i used GNU Bourne Again Shell for scripting, and i wondered if all of my longstandingly Bourne Shell established practices were seamlessly portable. So i did some research, and in this article i highlight some code constructs i found that work in Bourne Shell and do not work as expected in Bourne Again Shell. Code currently interpreted by /bin/sh and containing such constructs must be reviewed if will be interpreted by /bin/bash.

As it stands, i will focus on reserved words and built-ins, brace expansion and pipeline subprocesses.