Re: Bug#291026: Executing a command, if present, without 'command not found' message, if not present

[Thomas Hood <jdthood@yahoo.co.uk>]

Tollef Fog Heen wrote:
> If it's bash-only, wouldn't using bash + command -v be easier? :)

It would be easier, but it would also have the disadvantage that
command -v sometimes prints strings that are not executable commands
(#291197).  This means that if the administrator does chmod ugo-x
on a program thinking that this will disable it, command -v will
still report the same path for the program and the attempt to run
it will fail.  Ideally our code would avoid this, although I admit
that this is a relatively minor issue.

Earlier in #291026 I showed how to fix up command -v by doing further
testing on its output.  The code I gave was even POSIXly correct (but
complex).  However, now I am looking for something that implements:

   Try command #1 and if it didn't run because the command
   was not found, try command #2

rather than implementing:

   If command #1 looks runnable then try command #1,
   otherwise run command #2

-- 
Thomas