Re: [Shell Command Language][shortcomings of command utlity][improving robustness of POSIX shells]

[Harald van Dijk via austin-group-l at The Open Group]

On 12/04/2021 20:22, (Joerg Schilling) wrote:
Harald van Dijk <a...@gigawatt.nl> wrote:
On 12/04/2021 12:47, (Joerg Schilling) wrote:
Do you have a private variant og ksh93v?

I get the same behavior from  ksh88, the ksh93 from OpenSolaris and ksh93v.

I don't. I was testing with ksh built from
<https://github.com/att/ast/archive/93v.tar.gz>. I will try to figure
out why I am getting different results from you.

OK, it depends on usage, so you may have tested the "wrong" way:

ksh93 -c 'PATH=/tmp/:$PATH; gcc'
gcc: no input files

ksh93 -ic 'PATH=/tmp/:$PATH; gcc'
ksh93: gcc: not found [Datei oder Verzeichnis nicht gefunden]

ksh93 -c 'PATH=/tmp/:$PATH; gcc; hash'
ksh93[1]: gcc: not found [Datei oder Verzeichnis nicht gefunden]
gcc=/tmp/gcc

ksh93 -c 'PATH=/tmp/:$PATH; gcc; echo'
ksh93[1]: gcc: not found [Datei oder Verzeichnis nicht gefunden]

this looks strange...

Ah, good catch, thanks. Multiple shells have an optimisation where a 
command invocation at the last step, when no traps are active, is 
implicitly performed by exec without a fork, as if the exec builtin had 
been used. ksh apparently has a mismatch between the command lookup in 
the two cases.

Cheers,
Harald van Dijk