diff --git a/bin/compton-trans b/bin/compton-trans
index 4e55775..7576abc 100755
--- a/bin/compton-trans
+++ b/bin/compton-trans
@@ -26,6 +26,7 @@ opacity=
 cur=
 i=
 
+# Read options
 while getopts "scn:w:o:" option; do
   case "$option" in
     s) wprefix=''; window='' ;;
@@ -37,9 +38,14 @@ while getopts "scn:w:o:" option; do
     n) wprefix='-name '; window="$OPTARG" ;;
     w) wprefix='-id '; window="$OPTARG" ;;
     o) opacity="$OPTARG" ;;
+    \?) exit 1;;
   esac
 done
 
+# Read positional arguments
+shift $(($OPTIND - 1))
+[ -n "$1" ] && opacity="$1"
+
 # Validate opacity value
 if [ -z "$opacity" ]; then
 	echo "No opacity specified."
diff --git a/man/compton-trans.1 b/man/compton-trans.1
index 97b4d34..995ab87 100644
--- a/man/compton-trans.1
+++ b/man/compton-trans.1
@@ -6,7 +6,7 @@ compton\-trans \- an opacity setter tool
 
 .SH SYNOPSIS
 .nf
-.B compton-trans [-wncs] [window] -o [opacity]
+.B compton-trans [-w WINDOW_ID] [-n WINDOW_NAME] [-c] [-s] OPACITY
 .fi
 
 .SH DESCRIPTION