Re: Check for another program availability

If the program can be found in $ENV{'PATH'} when it is installed, then just trying to execute it will either succeed or fail, no need to search first. See system and exec.

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

Comment on Re: Check for another program availability Download Code

Replies are listed 'Best First'.
Re^2: Check for another program availability by Radiola (Monk) on Apr 14, 2021 at 06:20 UTC
I’ll sometimes do this as an explicit pre-flight check. If so, it’s either because: I use this program deep in the code and I don’t want to have to unroll a bunch of state (or fail and leave a broken mess) if I get halfway through and then find a critical external program is missing. I want to be unusually user-friendly for a Unix program. Seriously, sometimes the failure that results “naturally” is misleading and will leave the user (usually me) scratching their head and having to troubleshoot. I can save them (myself) a bunch of time if I simply tell them (me) what's wrong. I agree there’s no point to checking for availability on the line before you try to run the program; you might as well just process the error from `system` or whatever. – Aaron Preliminary operational tests were inconclusive. (The damn thing blew up.)	[reply] [d/l]

Replies are listed 'Best First'.

Re^2: Check for another program availability
by Radiola (Monk) on Apr 14, 2021 at 06:20 UTC

I’ll sometimes do this as an explicit pre-flight check. If so, it’s either because:

I use this program deep in the code and I don’t want to have to unroll a bunch of state (or fail and leave a broken mess) if I get halfway through and then find a critical external program is missing.
I want to be unusually user-friendly for a Unix program. Seriously, sometimes the failure that results “naturally” is misleading and will leave the user (usually me) scratching their head and having to troubleshoot. I can save them (myself) a bunch of time if I simply tell them (me) what's wrong.

I agree there’s no point to checking for availability on the line before you try to run the program; you might as well just process the error from system or whatever.

– Aaron
Preliminary operational tests were inconclusive. (The damn thing blew up.)

[reply]
[d/l]