diff --git a/spec/integrations/rebound_bracket_spec.rb b/spec/integrations/rebound_bracket_spec.rb
new file mode 100644
index 0000000..8b420f0
--- /dev/null
+++ b/spec/integrations/rebound_bracket_spec.rb
@@ -0,0 +1,13 @@
+describe 'rebinding [' do
+  context 'initialized before sourcing the plugin' do
+    before do
+      session.run_command("function [ { $commands[\\[] \"$@\" }")
+      session.clear_screen
+    end
+
+    it 'executes the custom behavior and the built-in behavior' do
+      session.send_string('asdf')
+      wait_for { session.content }.to eq('asdf')
+    end
+  end
+end
diff --git a/src/async.zsh b/src/async.zsh
index 124c9ac..1d1e76d 100644
--- a/src/async.zsh
+++ b/src/async.zsh
@@ -63,7 +63,7 @@ _zsh_autosuggest_async_pty_create() {
 	typeset -h REPLY
 
 	# If we won't get a fd back from zpty, try to guess it
-	if [ $_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD -eq 0 ]; then
+	if (( ! $_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD )); then
 		integer -l zptyfd
 		exec {zptyfd}>&1  # Open a new file descriptor (above 10).
 		exec {zptyfd}>&-  # Close it so it's free to be used by zpty.
diff --git a/src/bind.zsh b/src/bind.zsh
index be0d164..ed9a977 100644
--- a/src/bind.zsh
+++ b/src/bind.zsh
@@ -88,13 +88,13 @@ _zsh_autosuggest_bind_widgets() {
 
 	# Find every widget we might want to bind and bind it appropriately
 	for widget in ${${(f)"$(builtin zle -la)"}:#${(j:|:)~ignore_widgets}}; do
-		if [ ${ZSH_AUTOSUGGEST_CLEAR_WIDGETS[(r)$widget]} ]; then
+		if [[ -n ${ZSH_AUTOSUGGEST_CLEAR_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget clear
-		elif [ ${ZSH_AUTOSUGGEST_ACCEPT_WIDGETS[(r)$widget]} ]; then
+		elif [[ -n ${ZSH_AUTOSUGGEST_ACCEPT_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget accept
-		elif [ ${ZSH_AUTOSUGGEST_EXECUTE_WIDGETS[(r)$widget]} ]; then
+		elif [[ -n ${ZSH_AUTOSUGGEST_EXECUTE_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget execute
-		elif [ ${ZSH_AUTOSUGGEST_PARTIAL_ACCEPT_WIDGETS[(r)$widget]} ]; then
+		elif [[ -n ${ZSH_AUTOSUGGEST_PARTIAL_ACCEPT_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget partial_accept
 		else
 			# Assume any unspecified widget might modify the buffer
@@ -106,13 +106,13 @@ _zsh_autosuggest_bind_widgets() {
 # Given the name of an original widget and args, invoke it, if it exists
 _zsh_autosuggest_invoke_original_widget() {
 	# Do nothing unless called with at least one arg
-	[ $# -gt 0 ] || return
+	(( $# )) || return
 
 	local original_widget_name="$1"
 
 	shift
 
-	if [ $widgets[$original_widget_name] ]; then
+	if (( ${+widgets[$original_widget_name]} )); then
 		zle $original_widget_name -- $@
 	fi
 }
diff --git a/src/highlight.zsh b/src/highlight.zsh
index aa5a427..273c03d 100644
--- a/src/highlight.zsh
+++ b/src/highlight.zsh
@@ -7,7 +7,7 @@
 _zsh_autosuggest_highlight_reset() {
 	typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
 
-	if [ -n "$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT" ]; then
+	if [[ -n "$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT" ]]; then
 		region_highlight=("${(@)region_highlight:#$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT}")
 		unset _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
 	fi
@@ -17,7 +17,7 @@ _zsh_autosuggest_highlight_reset() {
 _zsh_autosuggest_highlight_apply() {
 	typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
 
-	if [ $#POSTDISPLAY -gt 0 ]; then
+	if (( $#POSTDISPLAY )); then
 		typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT="$#BUFFER $(($#BUFFER + $#POSTDISPLAY)) $ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE"
 		region_highlight+=("$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT")
 	else
diff --git a/src/start.zsh b/src/start.zsh
index 6fa8ce9..6f48ab6 100644
--- a/src/start.zsh
+++ b/src/start.zsh
@@ -15,7 +15,7 @@ _zsh_autosuggest_start() {
 	# to the widget list variables to take effect on the next precmd.
 	add-zsh-hook precmd _zsh_autosuggest_bind_widgets
 
-	if [ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]; then
+	if [[ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]]; then
 		_zsh_autosuggest_async_start
 	fi
 }
diff --git a/src/widgets.zsh b/src/widgets.zsh
index 8710c02..8a31133 100644
--- a/src/widgets.zsh
+++ b/src/widgets.zsh
@@ -13,14 +13,14 @@ _zsh_autosuggest_disable() {
 _zsh_autosuggest_enable() {
 	unset _ZSH_AUTOSUGGEST_DISABLED
 
-	if [ $#BUFFER -gt 0 ]; then
+	if (( $#BUFFER )); then
 		_zsh_autosuggest_fetch
 	fi
 }
 
 # Toggle suggestions (enable/disable)
 _zsh_autosuggest_toggle() {
-	if [ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]; then
+	if [[ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]]; then
 		_zsh_autosuggest_enable
 	else
 		_zsh_autosuggest_disable
@@ -54,35 +54,35 @@ _zsh_autosuggest_modify() {
 	retval=$?
 
 	# Don't fetch a new suggestion if there's more input to be read immediately
-	if [[ $PENDING > 0 ]] || [[ $KEYS_QUEUED_COUNT > 0 ]]; then
+	if (( $PENDING > 0 )) || (( $KEYS_QUEUED_COUNT > 0 )); then
 		return $retval
 	fi
 
 	# Optimize if manually typing in the suggestion
-	if [ $#BUFFER -gt $#orig_buffer ]; then
+	if (( $#BUFFER > $#orig_buffer )); then
 		local added=${BUFFER#$orig_buffer}
 
 		# If the string added matches the beginning of the postdisplay
-		if [ "$added" = "${orig_postdisplay:0:$#added}" ]; then
+		if [[ "$added" = "${orig_postdisplay:0:$#added}" ]]; then
 			POSTDISPLAY="${orig_postdisplay:$#added}"
 			return $retval
 		fi
 	fi
 
 	# Don't fetch a new suggestion if the buffer hasn't changed
-	if [ "$BUFFER" = "$orig_buffer" ]; then
+	if [[ "$BUFFER" = "$orig_buffer" ]]; then
 		POSTDISPLAY="$orig_postdisplay"
 		return $retval
 	fi
 
 	# Bail out if suggestions are disabled
-	if [ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]; then
+	if [[ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]]; then
 		return $?
 	fi
 
 	# Get a new suggestion if the buffer is not empty after modification
-	if [ $#BUFFER -gt 0 ]; then
-		if [ -z "$ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE" -o $#BUFFER -le "$ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE" ]; then
+	if (( $#BUFFER > 0 )); then
+		if [[ -z "$ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE" ]] || (( $#BUFFER <= $ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE )); then
 			_zsh_autosuggest_fetch
 		fi
 	fi
@@ -105,7 +105,7 @@ _zsh_autosuggest_fetch() {
 _zsh_autosuggest_suggest() {
 	local suggestion="$1"
 
-	if [ -n "$suggestion" ] && [ $#BUFFER -gt 0 ]; then
+	if [[ -n "$suggestion" ]] && (( $#BUFFER )); then
 		POSTDISPLAY="${suggestion#$BUFFER}"
 	else
 		unset POSTDISPLAY
@@ -118,12 +118,12 @@ _zsh_autosuggest_accept() {
 
 	# When vicmd keymap is active, the cursor can't move all the way
 	# to the end of the buffer
-	if [ "$KEYMAP" = "vicmd" ]; then
+	if [[ "$KEYMAP" = "vicmd" ]]; then
 		max_cursor_pos=$((max_cursor_pos - 1))
 	fi
 
 	# Only accept if the cursor is at the end of the buffer
-	if [ $CURSOR -eq $max_cursor_pos ]; then
+	if [[ $CURSOR = $max_cursor_pos ]]; then
 		# Add the suggestion to the buffer
 		BUFFER="$BUFFER$POSTDISPLAY"
 
@@ -165,7 +165,7 @@ _zsh_autosuggest_partial_accept() {
 	retval=$?
 
 	# If we've moved past the end of the original buffer
-	if [ $CURSOR -gt $#original_buffer ]; then
+	if (( $CURSOR > $#original_buffer )); then
 		# Set POSTDISPLAY to text right of the cursor
 		POSTDISPLAY="$RBUFFER"
 
diff --git a/zsh-autosuggestions.zsh b/zsh-autosuggestions.zsh
index 6cbaf05..3878d25 100644
--- a/zsh-autosuggestions.zsh
+++ b/zsh-autosuggestions.zsh
@@ -209,13 +209,13 @@ _zsh_autosuggest_bind_widgets() {
 
 	# Find every widget we might want to bind and bind it appropriately
 	for widget in ${${(f)"$(builtin zle -la)"}:#${(j:|:)~ignore_widgets}}; do
-		if [ ${ZSH_AUTOSUGGEST_CLEAR_WIDGETS[(r)$widget]} ]; then
+		if [[ -n ${ZSH_AUTOSUGGEST_CLEAR_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget clear
-		elif [ ${ZSH_AUTOSUGGEST_ACCEPT_WIDGETS[(r)$widget]} ]; then
+		elif [[ -n ${ZSH_AUTOSUGGEST_ACCEPT_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget accept
-		elif [ ${ZSH_AUTOSUGGEST_EXECUTE_WIDGETS[(r)$widget]} ]; then
+		elif [[ -n ${ZSH_AUTOSUGGEST_EXECUTE_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget execute
-		elif [ ${ZSH_AUTOSUGGEST_PARTIAL_ACCEPT_WIDGETS[(r)$widget]} ]; then
+		elif [[ -n ${ZSH_AUTOSUGGEST_PARTIAL_ACCEPT_WIDGETS[(r)$widget]} ]]; then
 			_zsh_autosuggest_bind_widget $widget partial_accept
 		else
 			# Assume any unspecified widget might modify the buffer
@@ -227,13 +227,13 @@ _zsh_autosuggest_bind_widgets() {
 # Given the name of an original widget and args, invoke it, if it exists
 _zsh_autosuggest_invoke_original_widget() {
 	# Do nothing unless called with at least one arg
-	[ $# -gt 0 ] || return
+	(( $# )) || return
 
 	local original_widget_name="$1"
 
 	shift
 
-	if [ $widgets[$original_widget_name] ]; then
+	if (( ${+widgets[$original_widget_name]} )); then
 		zle $original_widget_name -- $@
 	fi
 }
@@ -246,7 +246,7 @@ _zsh_autosuggest_invoke_original_widget() {
 _zsh_autosuggest_highlight_reset() {
 	typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
 
-	if [ -n "$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT" ]; then
+	if [[ -n "$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT" ]]; then
 		region_highlight=("${(@)region_highlight:#$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT}")
 		unset _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
 	fi
@@ -256,7 +256,7 @@ _zsh_autosuggest_highlight_reset() {
 _zsh_autosuggest_highlight_apply() {
 	typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT
 
-	if [ $#POSTDISPLAY -gt 0 ]; then
+	if (( $#POSTDISPLAY )); then
 		typeset -g _ZSH_AUTOSUGGEST_LAST_HIGHLIGHT="$#BUFFER $(($#BUFFER + $#POSTDISPLAY)) $ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE"
 		region_highlight+=("$_ZSH_AUTOSUGGEST_LAST_HIGHLIGHT")
 	else
@@ -278,14 +278,14 @@ _zsh_autosuggest_disable() {
 _zsh_autosuggest_enable() {
 	unset _ZSH_AUTOSUGGEST_DISABLED
 
-	if [ $#BUFFER -gt 0 ]; then
+	if (( $#BUFFER )); then
 		_zsh_autosuggest_fetch
 	fi
 }
 
 # Toggle suggestions (enable/disable)
 _zsh_autosuggest_toggle() {
-	if [ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]; then
+	if [[ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]]; then
 		_zsh_autosuggest_enable
 	else
 		_zsh_autosuggest_disable
@@ -319,35 +319,35 @@ _zsh_autosuggest_modify() {
 	retval=$?
 
 	# Don't fetch a new suggestion if there's more input to be read immediately
-	if [[ $PENDING > 0 ]] || [[ $KEYS_QUEUED_COUNT > 0 ]]; then
+	if (( $PENDING > 0 )) || (( $KEYS_QUEUED_COUNT > 0 )); then
 		return $retval
 	fi
 
 	# Optimize if manually typing in the suggestion
-	if [ $#BUFFER -gt $#orig_buffer ]; then
+	if (( $#BUFFER > $#orig_buffer )); then
 		local added=${BUFFER#$orig_buffer}
 
 		# If the string added matches the beginning of the postdisplay
-		if [ "$added" = "${orig_postdisplay:0:$#added}" ]; then
+		if [[ "$added" = "${orig_postdisplay:0:$#added}" ]]; then
 			POSTDISPLAY="${orig_postdisplay:$#added}"
 			return $retval
 		fi
 	fi
 
 	# Don't fetch a new suggestion if the buffer hasn't changed
-	if [ "$BUFFER" = "$orig_buffer" ]; then
+	if [[ "$BUFFER" = "$orig_buffer" ]]; then
 		POSTDISPLAY="$orig_postdisplay"
 		return $retval
 	fi
 
 	# Bail out if suggestions are disabled
-	if [ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]; then
+	if [[ -n "${_ZSH_AUTOSUGGEST_DISABLED+x}" ]]; then
 		return $?
 	fi
 
 	# Get a new suggestion if the buffer is not empty after modification
-	if [ $#BUFFER -gt 0 ]; then
-		if [ -z "$ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE" -o $#BUFFER -le "$ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE" ]; then
+	if (( $#BUFFER > 0 )); then
+		if [[ -z "$ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE" ]] || (( $#BUFFER <= $ZSH_AUTOSUGGEST_BUFFER_MAX_SIZE )); then
 			_zsh_autosuggest_fetch
 		fi
 	fi
@@ -370,7 +370,7 @@ _zsh_autosuggest_fetch() {
 _zsh_autosuggest_suggest() {
 	local suggestion="$1"
 
-	if [ -n "$suggestion" ] && [ $#BUFFER -gt 0 ]; then
+	if [[ -n "$suggestion" ]] && (( $#BUFFER )); then
 		POSTDISPLAY="${suggestion#$BUFFER}"
 	else
 		unset POSTDISPLAY
@@ -383,12 +383,12 @@ _zsh_autosuggest_accept() {
 
 	# When vicmd keymap is active, the cursor can't move all the way
 	# to the end of the buffer
-	if [ "$KEYMAP" = "vicmd" ]; then
+	if [[ "$KEYMAP" = "vicmd" ]]; then
 		max_cursor_pos=$((max_cursor_pos - 1))
 	fi
 
 	# Only accept if the cursor is at the end of the buffer
-	if [ $CURSOR -eq $max_cursor_pos ]; then
+	if [[ $CURSOR = $max_cursor_pos ]]; then
 		# Add the suggestion to the buffer
 		BUFFER="$BUFFER$POSTDISPLAY"
 
@@ -430,7 +430,7 @@ _zsh_autosuggest_partial_accept() {
 	retval=$?
 
 	# If we've moved past the end of the original buffer
-	if [ $CURSOR -gt $#original_buffer ]; then
+	if (( $CURSOR > $#original_buffer )); then
 		# Set POSTDISPLAY to text right of the cursor
 		POSTDISPLAY="$RBUFFER"
 
@@ -601,7 +601,7 @@ _zsh_autosuggest_async_pty_create() {
 	typeset -h REPLY
 
 	# If we won't get a fd back from zpty, try to guess it
-	if [ $_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD -eq 0 ]; then
+	if (( ! $_ZSH_AUTOSUGGEST_ZPTY_RETURNS_FD )); then
 		integer -l zptyfd
 		exec {zptyfd}>&1  # Open a new file descriptor (above 10).
 		exec {zptyfd}>&-  # Close it so it's free to be used by zpty.
@@ -662,7 +662,7 @@ _zsh_autosuggest_start() {
 	# to the widget list variables to take effect on the next precmd.
 	add-zsh-hook precmd _zsh_autosuggest_bind_widgets
 
-	if [ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]; then
+	if [[ -n "${ZSH_AUTOSUGGEST_USE_ASYNC+x}" ]]; then
 		_zsh_autosuggest_async_start
 	fi
 }