Path: utzoo!utgpu!cs.utexas.edu!sdd.hp.com!think.com!yale!cmcl2!kramden.acf.nyu.edu!brnstnd
From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: alt.sources.d
Subject: Re: Multiple executables in path (Was: NON-SOURCE POSTINGS CONSIDERED HARMFUL!)
Message-ID: <17501:Jan2414:21:3991@kramden.acf.nyu.edu>
Date: 24 Jan 91 14:21:39 GMT
References: <9688:Jan2313:09:4391@kramden.acf.nyu.edu> <8833@star.cs.vu.nl> <5648@idunno.Princeton.EDU>
Organization: IR
Lines: 103

Ya want other behaviors? Fine, ya get other behaviors. These all use the
same strategy as the original.

Original:

  echo `echo "$PATH" | tr : '\012' | sed -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed 's:/\.\./:/:g'

The same thing, but with marks from ls showing the type of each file:

  ls -dF `echo "$PATH" | tr : '\012' | sed -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed 's:/\.\./:/:g'

The same thing, but following symbolic links:

  ls -dFL `echo "$PATH" | tr : '\012' | sed -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed 's:/\.\./:/:g'

The same thing, but showing only executables:

  ls -dFL `echo "$PATH" | tr : '\012' | sed -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed -n -e 's:/\.\./:/:g' -e '/*$/p'

The same thing, but removing the *:

  ls -dFL `echo "$PATH" | tr : '\012' | sed -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed -n -e 's:/\.\./:/:g' -e 's/*$//p'

The same thing, but showing only the first executable:

  ls -dFL `echo "$PATH" | tr : '\012' | sed -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed -n -e 's:/\.\./:/:g' -e 's/*$//p' | head -1

Same as the first one, but converting . in PATH into the actual cwd:

  setenv WD "`pwd`"
  echo `echo "$PATH" | tr : '\012' | sed -e 's:^\.$:'"$WD": -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed 's:/\.\./:/:g'

The same thing, but with ./ instead of `pwd`/:

  echo `echo "$PATH" | tr : '\012' | sed -e 's:^\.$:'"$WD": -e 's:$:/!:1': -e 's:^:/.[.]:'`\
    | sed -e 's:/\.\./:/:g' -e 's:^'"$WD"'/:./:g'

You can easily combine these to make other behaviors if you want, e.g.,
to just show the first executable including in ., or whatever.

If you want to quote a command for csh or sh, e.g., to make a csh alias,
or to pass something to sh -c or csh -cf: Use quote and makealias, which
have been running around since I posted them in 1988. You can pick up a
pile of random shell tricks from pub/hier/misc/faq-shell via anonymous
ftp to 128.122.128.22.

If you want to put these in a script instead: Replace !:1 with '"$1"',
and top the script with #!/bin/csh -f.

If you want to accept aliases from .cshrc: Same, but remove the -f.

In article <5648@idunno.Princeton.EDU> pfalstad@phoenix.Princeton.EDU (Paul Falstad) writes:
> If you don't agree with Dan, and want
> to fix the csh version to exclude non-executables, after deciphering the csh
> brain-damage you'd discover that there's no way to change it.

Again, the deciphering is as simple as ``alias which'', but it's a fair
accusation. Wrong, but fair.

> Perhaps
> since Dan can't fix his which, he's decided that it's OK the way it is.

An interesting thought.

> (That's only a suggestion.  He probably does like which to have that behavior.)

Obviously.

> But Tom's solution can easily be changed to have either behavior.

So what? So can any reasonable solution.

> That's nice, but the fact is many people do have . in their path (it's
> last in the default path at our site).  You're saying, "Well, my version
> doesn't work if you have . in your path, so don't put . in your path."
> "Doctor, it hurts when I do this."  "So don't do that."

Again, wrong, though fair.

> Again I could ask, does your csh alias behave this way because you
> designed it to, or because there's no other way it could act?

I think I've answered that question.

> >)> Had you read the documentation of `which5', you would have known it's not
> >)> that trivial to get things right.
> >)Different people will prefer different behaviors of ``which''; [...]
> >Agreed.  But some types of behavior are questionable at best, ridiculous
> >at worst.
> Dan prefers the behavior of his which because the crufty language it's
> written in allows no other behavior.

Now, now, don't make silly accusations without thinking things through
first.

---Dan