Re: RFE & RFC: testing executability

[PePa]

On 10/01/2017 11:31 AM, L A Walsh wrote:
> cmd=$(PATH=/stdpath type -p cmd)

I use this kind of construction with 'type -p' regularly:

! cmd=$(type -p cmd) && echo "ABEND: Executable cmd not in PATH" && exit

Then $cmd can be used to execute the binary, and not some alias or 
function. This is the whole point of the '-p' flag, otherwise you would 
use the '-a' flag. When 'cmd' is in the PATH, it is found even when it 
isn't executable, so it could make sense to do 'text -x "$cmd".

> the "-x" test failed if cmd was an alias, function or preceded by
> 'command' (which I was surprised, also, to find, "not executable").

Note that 'test -x' only tests actual files, so if you do 'test -x grep' 
and there is no executable file 'grep' in $PWD then it tests false.

> Comments?  Reasonable?  Wanted? Doable or patchable?

It follows that you cannot use 'test -x' on functions or aliases, as 
they are not files. I don't understand your use case. Do you want a 
'type -a' kind of functionality? What do you want to test?? I think you 
can already do what you need in bash.

Peter