Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!accuvax.nwu.edu!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.questions
Subject: Re: help with csh alias
Message-ID: <16873@mimsy.UUCP>
Date: 12 Apr 89 04:51:24 GMT
References: <8077@boulder.Colorado.EDU>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 33

In article <8077@boulder.Colorado.EDU> cdash@boulder.Colorado.EDU
(Charles Shub) writes:
>desired version
>	mycommand `expr <nocolon> - 5` other args

This is easy in sh, harder in csh; in csh it must be done in two
steps.  What you want is

	echo $1 | sed s/://

spliced in for <nocolon>; the natural way to express this would be

	expr `echo $1 | sed s/://` - 5

and so the natural way to express the whole thing would be

	mycommand `expr \`echo $1 | sed s/://\` - 5` morestuff

This works properly in sh, but not csh.  So we have to resort to
shell variables:

	set tmp=`echo $1 | sed s/://`; mycommand `expr $tmp - 5` morestuff

or two levels of alias:

	alias part1 'expr `echo $1 | sed s/://` - 5'
	mycommand `part1` morestuff

or anything equivalent to this, as long as it does it `one splice
at a time'.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris