scripts/zat: Fix position saving

Calling zathura over stdin prevents saving position.
We use stdin for non-supported files only.

.scripts/zat

@@ -3,17 +3,11 @@
 [ -z "$VIEWER" ] && VIEWER="zathura --fork"
 
 for i; do
-	basename=${i##*/}
-	ext=${basename##*.}
-
-	case "$ext" in
-	bz2) bzcat "$i" ;;
-	bz) bzcat "$i" ;;
-	gz) zcat "$i" ;;
-	lrz) lrzcat "$i" ;;
-	lz) lzcat "$i" ;;
-	lz4) lz4cat "$i" ;;
-	xz) xzcat "$i" ;;
-	*) cat "$i" ;;
-	esac | $VIEWER -
+	if $(file -i -b "$i" | grep -qi 'pdf\|postscript\|djvu'); then
+		$VIEWER "$i"
+	else
+		## The drawback of reading from stdin is that zathura will not save the
+		## position.
+		acat "$i" | $VIEWER -
+	fi
 done