Find the path of a shell command

[Paulo da Silva]

Às 19:14 de 12/10/22, Jon Ribbens escreveu:
> On 2022-10-12, Paulo da Silva <p_d_a_s_i_l_v_a_ns at nonetnoaddress.pt> wrote:
>> Às 05:00 de 12/10/22, Paulo da Silva escreveu:
>>> Hi!
>>>
>>> The simple question: How do I find the full path of a shell command
>>> (linux), i.e. how do I obtain the corresponding of, for example,
>>> "type rm" in command line?
>>>
>>> The reason:
>>> I have python program that launches a detached rm. It works pretty well
>>> until it is invoked by cron! I suspect that for cron we need to specify
>>> the full path.
>>> Of course I can hardcode /usr/bin/rm. But, is rm always in /usr/bin?
>>> What about other commands?
>>>
>> Thank you all who have responded so far.
>> I think that the the suggestion of searching the PATH env seems the best.
>> Another thing that I thought of is that of the 'which', but, to avoid
>> the mentioned recurrent problem of not knowing where 'which' is I would
>> use 'type' instead. 'type' is a bash (sh?) command.
> 
> If you're using subprocess.run / subprocess.Popen then the computer is
> *already* searching PATH for you.
Yes, and it works out of cron.
> Your problem must be that your cron
> job is being run without PATH being set, perhaps you just need to edit
> your crontab to set PATH to something sensible.
I could do that, but I am using /etc/cron.* for convenience.

> Or just hard-code your
> program to run '/bin/rm' explicitly, which should always work (unless
> you're on Windows, of course!)
It can also be in /bin, at least.
A short idea is to just check /bin/rm and /usr/bin/rm, but I prefer 
searching thru PATH env. It only needs to do that once.