--- ray/src/util/fieldcomb.csh	2005/09/05 16:13:08	2.5
+++ ray/src/util/fieldcomb.csh	2005/09/06 15:34:46	2.6
@@ -1,5 +1,5 @@
 #!/bin/csh -f
-# RCSid $Id: fieldcomb.csh,v 2.5 2005/09/05 16:13:08 greg Exp $
+# RCSid $Id: fieldcomb.csh,v 2.6 2005/09/06 15:34:46 greg Exp $
 #
 # Combine alternate lines in full frames for field rendering
 #
@@ -34,10 +34,14 @@ while ($#argv > 1)
 	endsw
 	shift argv
 end
-if ($#argv < 2 || ($?outfile && $#argv > 2)) then
+if ($#argv < 2) then
 	echo "Usage: $0 [-e|-o][-r] [-f combined.pic] field1.pic field2.pic .."
 	exit 1
 endif
+if ($?outfile && $#argv > 2) then
+	echo "Cannot use -f option with more than two input files"
+	exit 1
+endif
 set f1=$argv[1]:q
 set ext=$f1:e
 set basenm="`echo $f1:q | sed 's/[0-9]*\.'$ext'//'`"
@@ -61,7 +65,9 @@ while ($curfi < $#fields)
 		set fid=$curfr
 	endif
        	set outf="${basenm}C$fid.$ext"
-	if ($?outfile) set outf=$outfile:q
+	if ($?outfile) then
+		set outf=$outfile:q
+	endif
 	pcomb -e 'ro=ri(fld); go=gi(fld); bo=bi(fld)' \
 		-e 'yd=yres-1-y; odd=.5*yd-floor(.5*yd)-.25' \
 		-e "fld=if(odd,2-$odd_first,1+$odd_first)" \