diff --git a/libexec/rbenv-completions b/libexec/rbenv-completions
index 6de09ed2..196212e4 100755
--- a/libexec/rbenv-completions
+++ b/libexec/rbenv-completions
@@ -11,7 +11,7 @@ if [ -z "$COMMAND" ]; then
 fi
 
 COMMAND_PATH="$(command -v "rbenv-$COMMAND" || command -v "rbenv-sh-$COMMAND")"
-if grep -i "^\([#%]\|--\|//\) provide rbenv completions" "$COMMAND_PATH" >/dev/null; then
+if grep -iE "^([#%]|--|//) provide rbenv completions" "$COMMAND_PATH" >/dev/null; then
   shift
   exec "$COMMAND_PATH" --complete "$@"
 fi
diff --git a/test/completions.bats b/test/completions.bats
index 0feccfa9..9091f082 100644
--- a/test/completions.bats
+++ b/test/completions.bats
@@ -18,7 +18,7 @@ create_command() {
 
 @test "command with completion support" {
   create_command "rbenv-hello" "#!$BASH
-# provide rbenv completions
+# Provide rbenv completions
 if [[ \$1 = --complete ]]; then
   echo hello
 else