Date: Sun, 1 Feb 1998 16:11:59 -0500 (EST) From: Brian Clapper <bmc@WillsCreek.COM> To: "Joe \"Marcus\" Clarke" <marcus@miami.edu> Cc: "Matthew D. Fuller" <fullermd@futuresouth.com>, laszlo vagner <kf7nn@mutsgo.dyn.ml.org>, Greg Lehey <grog@lemis.com>, questions@FreeBSD.ORG Subject: Re: rehash missing Message-ID: <199802012111.QAA05678@current.willscreek.com> In-Reply-To: <Pine.OSF.3.96.980201050915.1311B-100000@jaguar.ir.miami.edu> References: <Pine.BSF.3.96.980201034222.21493B-100000@shell.futuresouth.com> <Pine.OSF.3.96.980201050915.1311B-100000@jaguar.ir.miami.edu>
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On 1 February, 1998, at 05:09 (-0500)
"Joe \"Marcus\" Clarke" <marcus@miami.edu> wrote:
> A quick way to find out if a command is built into the shell or not, is
> to run 'which <command>'. It will tell you right waway.
Note that `which' won't tell you the command is a built-in unless you use
`csh' or `tcsh', where `which' itself is a built-in. In a shell for which
there is no `which' built-in (e.g., `ksh'), you'll end up running
`/usr/bin/which', and that "outside" command cannot possibly know about the
shell's built-in commands or its currently-established aliases. Try typing
which alias
inside `ksh'. You'll get no output. However, for most of the shells
supported by FreeBSD, there is typically a built-in command that
corresponds to `which'. For example:
---------------------------------------------------------------------------
SHELL COMMAND
---------------------------------------------------------------------------
tcsh which
csh which
sh type
ksh whence -v
type (which is nothing more than an alias for `whence -v'
bash type
zsh type
which
whence -v
---------------------------------------------------------------------------
Brian Clapper, bmc@WillsCreek.COM, http://WWW.WillsCreek.COM/
You should emulate your heros, but don't carry it too far. Especially
if they are dead.
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