Mailinglist Archive: opensuse (2876 mails)

[Randall R Schulz <rschulz@xxxxxxxxx>]

On Saturday 19 May 2007 10:15, Carlos F Lange wrote:
> ...
>
> Now, here is a puzzle:
>
>         clange@zico:~> which time
>         /usr/bin/time
>         clange@zico:~> type time
>         time is a shell keyword
>         clange@zico:~> time --help
>         bash: --help: command not found
>
>         real    0m0.011s
>         user    0m0.000s
>         sys     0m0.004s
>
> That is, in my case the built-in "time" has precedence, but "which"
> is giving the impression that I would be running /usr/bin/time. If I
> use the option -a:
>         clange@zico:~> which -a time
>         /usr/bin/time
>         clange@zico:~> type -a time
>         time is a shell keyword
>         time is /usr/bin/time

If the which command is the stock executable binary (often it's an alias 
to the BASH "type" built-in), then it does not know about built-ins in 
the shell that invoked and can tell you only about other stand-alone 
executables (binaries or scripts).


> Since "which" gives out nothing in the case of a shell built-in
> command, perhaps what it is doing everytime is 1) giving out nothing,
> 2) giving out /usr/bin/time in second place.
> So, "type" seems to be more useful here.

Type is more useful since it has a greater scope. If you're inured to 
typing "which," then create an alias for it:

alias which='type -p'

(The "-p" option causes type to emit full path names, which makes its 
output compatible with that of "which".)


You might want to know that there's a "-a" option to both "which" 
and "type" that cause them to print all instances of the named command 
in the PATH, instead of just the first one--the one you'll get if you 
just invoke the command without any path name qualification.


> Carlos FL


Randall Schulz
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