GNUism.

Index: bookman
--- bookman.orig
+++ bookman
@@ -83,9 +83,9 @@ done
 shift $(($OPTIND - 1))
 date=${date:-$(date +'%d %B %Y')}
 
-[[ $1 ]] || set -- $(while read; do echo $REPLY; done)
+[[ -n $1 ]] || set -- $(while read; do echo $REPLY; done)
 
-[[ $outfile ]] && post="$post >$outfile"
+[[ -n $outfile ]] && post="$post >$outfile"
 
 {
 	# Compute table of content from postscript output.
@@ -127,7 +127,7 @@ date=${date:-$(date +'%d %B %Y')}
 			name = $0
 		}
 		END {print ".XE"; print ".PX"}'
-	} | groff -Z -ms | head --lines=-1
+	} | groff -Z -ms | sed '$d'
 
 	# Output content, in gtroff intermediate format.
 	for f
