On Sun, Jun 26, 2005 at 09:32:36PM -0400, Ted Unangst wrote:
> On Sun, 26 Jun 2005, Peter Bako wrote:
>
> > #!/bin/sh
> > month=$1
> > day=$2
> > year=$3
> >
> > dayscount=$(expr ($year - 1900) * 365)
> > echo $dayscount
> > exit
> >
> > This will generate a "syntax error: `$year' unexpected" error. I have tried
> > all sorts of variations and I am not getting it!!! HELP!!!
>
> man sh says arithmetic expressions take double parens:
>
> dayscount=$((($year - 1900) * 365))
>
> don't forget about leap years.
Traditional Bourne shell doesn't have arithmetic substitutions so it
would be done with expr like this:
dayscount=$(expr $(expr $year - 1900) \* 365)
or even:
dayscount=`expr \`expr $year - 1900\` \* 365`
This only matters if your script needs to be portable.
--
stephen
