[Info-vax] Foreign commands ... newbie question

[Johnny Billquist]

On 2011-10-18 15.36, Bob Koehler wrote:
> In article<YbidnXOnLJEB0AHTnZ2dnUVZ_sudnZ2d at earthlink.com>, "John Reagan"<johnrreagan at earthlink.net>  writes:
>>
>> 'which' doesn't know about shell aliases so it isn't like "show symbol".
>> "alias" and "show symbol" are the same.
>
>     Guess again.  Like all things UNIX, that depends on which UNIX.

It isn't as much a question of which unix, as a question of which shell.

Unixes may have many small differences, but not really many big ones. 
They all treat the environment, the process relationships and 
inheritance between processes the same way.

And aliases don't exist at all, at the "unix" level. It's totally a 
concept inside the shell, and each shell can and will do it in its own, 
unique way, including not having them at all for some shells...

>     And "alias" is like "show symbol" filtered for foreign command
>     symbols.

Once more, that depends on the shell.
"alias" is a built-in command, or else a shell-script which in turn 
invoke some built-in command to extract information, as aliases aren't 
really exposed outside of the shell.

Oh, and the shell pretty much works the same no matter which flavor of 
Unix it runs under.

	Johnny