Re: [PATCH] Ensure the command found in the hash table exists, not only on POSIXLY_CORRECT

[Chet Ramey]

On 1/7/10 8:39 AM, Giuseppe Scrivano wrote:
> Hello,
> 
> what do you think about make this the default behavior, not only when
> POSIXLY_CORRECT is specified?  A `stat' is very fast, the cost of a
> stat+fork+exec is almost the same of a fork+exec.

If you want to make this your default behavior, enable the `checkhash'
option with shopt.


> I have a question: how bash should behave in the case you have:
> 
> -------------------------------------------
> export PATH=a:b:$PATH
> 
> mkdir a b
> 
> cat > b/prog.sh << EOF
> echo b/prog.sh
> EOF
> 
> chmod +x b/prog.sh
> 
> prog.sh
> 
> cat > a/prog.sh << EOF
> echo a/prog.sh
> EOF
> 
> chmod +x a/prog.sh
> 
> prog.sh
> -------------------------------------------
> 
> 
> Which prog.sh should be used in this case?  a/prog.sh or b/prog.sh?  The
> former has a higher precedence in PATH but the latter is the hashed
> value.

The hashed value should be preferred as long as it exists.  If you're
concerned about this being a problem, run `hash prog.sh' after creating
it.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/