Bug#218530: Summary of options for improving conditional rune for initscript calls

[Thomas Hood <jdthood@aglu.demon.nl>]

Summarizing, then: the choices are:

1. Stay with "if [ -x /usr/sbin/invoke-rc.d ] ; then"

2. Change to "#!/bin/bash ...  if type invoke-rc.d ; then"

3. Change to "if type invoke-rc.d ; then" and change policy to
   require that /bin/sh point to a shell that supports "type".

4. Change to "if invoke-rc.d --help > /dev/null 2>&1 ; then"


Other ideas which were shot down, with bullets:

5. Change to "if type -p invoke-rc.d > /dev/null 2>&1 ; then"

   * type's "-p" option is not available on dash
   * Also, there is no reason to rule out aliases/functions/builtins

6. Change to "if type invoke-rc.d > /dev/null 2>&1 ; then"

   * "type" is not available in posh

7. Change to "if command -v invoke-rc.d > /dev/null 2>&1 ; then"

   * "command -v" is not available in posh
   * "command -v" is an optional functionality according to
       http://www.opengroup.org/onlinepubs/009695399/utilities/

8. Change to "if which invoke-rc.d > /dev/null 2>&1 ; then"

   * which is in /usr/bin
   * woody's which is buggy

--
Thomas Hood