Path: utzoo!utgpu!cs.utexas.edu!convex!news
From: tchrist@convex.COM (Tom Christiansen)
Newsgroups: alt.sources.d
Subject: Re: Multiple executables in path (Was: NON-SOURCE POSTINGS CONSIDERED HARMFUL!)
Message-ID: <1991Jan19.105624.15369@convex.com>
Date: 19 Jan 91 10:56:24 GMT
References: <1991Jan17.224403.16050@convex.com> <MLEISHER.91Jan18165838@thrinakia.nmsu.edu> <17373:Jan1908:30:3191@kramden.acf.nyu.edu>
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Reply-To: tchrist@convex.COM (Tom Christiansen)
Organization: CONVEX Software Development, Richardson, TX
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From the keyboard of brnstnd@kramden.acf.nyu.edu (Dan Bernstein):
:Hmmm. I've always been satisfied with the speed of
:
:  alias which 'echo `echo "$PATH" | tr : '\''\012'\'' | sed -e '\''s+$+/\!:1+'\'' -e '\''s:^:/.[.]:'\''` | sed '\''s:/../:/:g'\'''

But it doesn't do the same thing as mine does, Dan.  Yours is more like this:

    for $file (@ARGV) {
	for $dir (split(/:/,$ENV{'PATH'})) {
	    print $path,"\n" if -x ($path="$dir/$file");
	} 
    }

except that it uses many more processes, runs more slowly, and is 
significantly more difficult to read and thus maintain.

But as I said, the original code does something different: it doesn't just
tell you which paths lead to a particular command.  Rather, it produces a
complete list of all commands in your $PATH with more than one path to
them, except for those duplicates that are just there due to symlinks to
the same executable and by the same name, such as /etc/foo ->
/usr/etc/foo.  That's why the $files{$name, $dev, $ino} array is kept.  I
doubt you can do the last part with a csh alias, and even if you could, I
wouldn't want to try to make sense out of it, unless of course it just
pointed to my script. :-)

--tom
--
"Hey, did you hear Stallman has replaced /vmunix with /vmunix.el?  Now
 he can finally have the whole O/S built-in to his editor like he
 always wanted!" --me (Tom Christiansen <tchrist@convex.com>)