Date: Wed, 14 May 1997 12:00:30 -0800 (AKDT) From: 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 Message-ID: <Pine.BSF.3.95q.970514114558.15079A-100000@aak.anchorage.net> 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 ...
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