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Date: Wed, 14 May 1997 12:00:30 -0800 (AKDT)
From: Steve Howe <un_x@anchorage.net>
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Reply-To: Steve Howe <un_x@anchorage.net>
To: Zahemszky Gabor <zgabor@CoDe.hu>
cc: FreeBSD questions <freebsd-questions@freebsd.org>, un_x@anchorage.net
Subject: Re: parameter expansion
In-Reply-To: <199705141303.PAA00546@CoDe.hu>
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On Wed, 14 May 1997, Zahemszky Gabor wrote:

> > t=file.gz.tar.gz
> > echo ${t%.gz}
> > echo ${t%%.gz}
> > 
> > i've been trying to figure out the difference between
> > using 1 or 2 "%" in my expansions, but haven't had any luck!
> > whether 1 or 2, i can't see any difference.
> > -------------------------------------------------------------------------
> Well, it has a difference, if you use joker characters that match
> more than one character (of course, there is only one: *):

you are right.  it only makes a difference if you use "*",
which will match the longest suffix possible.

> $ echo $MAIL			# SUFFIX
> /var/mail/zgabor
> $ echo ${MAIL%/*}		# matches only "/zgabor"
> /var/mail
> $ echo ${MAIL%%/*}		# matches "/var/mail/zgabor"
> 
> $
> 
> or another one:		# PREFIX
> $ echo ${MAIL#*/}
> var/mail/zgabor		# matches "/"
> $ echo ${MAIL##*/}
> zgabor			# matches "/var/mail/"
> $
> 
> Bye, Gabor

hey - thanks!

> PS: is it works in your sh?  On my 2.1.5 from sh, I got only:
> Syntax error: Bad substitution

yes - my example above works w/2.2.1.  why shouldn't it? :)

> --
#!/bin/ksh
Z='21N16I25C25E30, 40M30E33E25T15U!' ;IFS=' ABCDEFGHIJKLMNOPQRSTUVWXYZ ';
set $Z;for i { [[ $i = ? ]]&&print $i&&break;[[ $i = ??? ]]&&j=$i&&i=${i%?};
typeset -i40 i=8#$i;print -n ${i#???};[[ "$j" = ??? ]]&&print -n "${j#??} "&&
j=;typeset +i i;};IFS=' 0123456789 ';set $Z;X=;for i { [[ $i = , ]]&&i=2;
[[ $i = ?? ]]||typeset -l i;X="$X $i";typeset +l i;};print "$X"

i tried this thing with sh - but only got errors :(
(i was a little scared it would do something evil!)
i don't have ksh ...