diff --git a/fsub b/fsub
index 4a56445..887de3a 100755
--- a/fsub
+++ b/fsub
@@ -9,12 +9,11 @@ usage() {
 	exit 1
 }
 
-[ -z $1 ] && usage
-[ -f $1 ] || usage
-[ -z $2 ] || usage
-[ -f $FSUBRC ] || touch $FSUBRC
+[ -z "$1" ] && usage
+[ -f "$1" ] || usage
+[ -z "$2" ] || usage
+[ -f "$FSUBRC" ] || touch $FSUBRC
 
-cp $1 $1.bak
 awk '
 BEGIN {
 	n = 1
@@ -44,6 +43,5 @@ BEGIN {
 	print time
 	for(j = 0; j < linen; j++)
 		print lines[j]
-}' $1 | sed 's/\r//' > /tmp/fsub
-mv /tmp/fsub $1
-rm $1.bak
+}' "$1" | sed 's/\r//' > /tmp/fsub
+mv /tmp/fsub "$1"