diff --git a/scripts/speedwm-sxp b/scripts/speedwm-sxp
index 7d8946c..3db196e 100755
--- a/scripts/speedwm-sxp
+++ b/scripts/speedwm-sxp
@@ -21,5 +21,10 @@ OP="$(MENU_DATA | "$RUNLAUNCHER" -g 1 -l 40 -p 'Enter an S expression:')"
 [ -z "$OP" ] && exit 0
 
 # write expression
+
+FILE_CONTENTS="$(grep -v "$OP" "$CUSTOM_HISTFILE")"
+printf "%s\n" "$FILE_CONTENTS" > "$CUSTOM_HISTFILE" # prevent duplicates
+
+# add entry
 printf "%s\n" "$OP" >> "$CUSTOM_HISTFILE"
 printf "%s\n" "$OP"