diff --git a/history-substring-search.zsh b/history-substring-search.zsh
index 6bf8626..92627e5 100644
--- a/history-substring-search.zsh
+++ b/history-substring-search.zsh
@@ -106,20 +106,20 @@ history-substring-search-end() {
 history-substring-search-backward() {
   history-substring-search-begin
 
-  if [[ ($history_substring_search_match_number -ge 2 && $history_substring_search_match_number -le $history_substring_search_number_of_matches_plus_one) ]]; then
+  if [[ $history_substring_search_match_number -ge 2 && $history_substring_search_match_number -le $history_substring_search_number_of_matches_plus_one ]]; then
     let "history_substring_search_match_number = $history_substring_search_match_number - 1"
     history_substring_search_command_to_be_retrieved=$history[$history_substring_search_matches[$history_substring_search_match_number]]
     BUFFER=$history_substring_search_command_to_be_retrieved
     history-substring-search-highlight $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND
   else
-    if [[ ($history_substring_search_match_number -eq 1) ]]; then
+    if [[ $history_substring_search_match_number -eq 1 ]]; then
       # we will move out of the history_substring_search_matches
       let "history_substring_search_match_number = $history_substring_search_match_number - 1"
       history_substring_search_old_buffer_backward=$BUFFER
       BUFFER=$history_substring_search_search4later
       history-substring-search-highlight $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND
     else
-      if [[ ($history_substring_search_match_number -eq $history_substring_search_number_of_matches_plus_one ) ]]; then
+      if [[ $history_substring_search_match_number -eq $history_substring_search_number_of_matches_plus_one ]]; then
         # we will move back to the history_substring_search_matches
         let "history_substring_search_match_number = $history_substring_search_match_number - 1"
         BUFFER=$history_substring_search_old_buffer_forward
@@ -134,24 +134,24 @@ history-substring-search-backward() {
 history-substring-search-forward() {
   history-substring-search-begin
 
-  if [[ ($history_substring_search_match_number -eq $history_substring_search_number_of_matches_plus_one ) ]]; then
+  if [[ $history_substring_search_match_number -eq $history_substring_search_number_of_matches_plus_one ]]; then
     let "history_substring_search_match_number = $history_substring_search_match_number"
     history_substring_search_old_buffer_forward=$BUFFER
     BUFFER=$history_substring_search_search4later
     history-substring-search-highlight $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND
-  elif [[ ($history_substring_search_match_number -ge 0 && $history_substring_search_match_number -le $history_substring_search_number_of_matches_minus_one) ]]; then
+  elif [[ $history_substring_search_match_number -ge 0 && $history_substring_search_match_number -le $history_substring_search_number_of_matches_minus_one ]]; then
     let "history_substring_search_match_number = $history_substring_search_match_number + 1"
     history_substring_search_command_to_be_retrieved=$history[$history_substring_search_matches[$history_substring_search_match_number]]
     BUFFER=$history_substring_search_command_to_be_retrieved
     history-substring-search-highlight $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND
   else
-    if [[ ($history_substring_search_match_number -eq $history_substring_search_number_of_matches ) ]]; then
+    if [[ $history_substring_search_match_number -eq $history_substring_search_number_of_matches ]]; then
       let "history_substring_search_match_number = $history_substring_search_match_number + 1"
       history_substring_search_old_buffer_forward=$BUFFER
       BUFFER=$history_substring_search_search4later
       history-substring-search-highlight $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND
     else
-      if [[ ($history_substring_search_match_number -eq 0 ) ]]; then
+      if [[ $history_substring_search_match_number -eq 0 ]]; then
         let "history_substring_search_match_number = $history_substring_search_match_number + 1"
         BUFFER=$history_substring_search_old_buffer_backward
         history-substring-search-highlight $HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND