diff --git a/process.c b/process.c
index eeafc4c483..df284a135c 100644
--- a/process.c
+++ b/process.c
@@ -3083,7 +3083,7 @@ NORETURN(static VALUE f_exec(int c, const VALUE *a, VALUE _));
* or contain meta characters:
*
* exec('if true; then echo "Foo"; fi') # Shell reserved word.
- * exec('echo') # Built-in.
+ * exec('exit') # Built-in.
* exec('date > date.tmp') # Contains meta character.
*
* The command line may also contain arguments and options for the command:
@@ -4772,14 +4772,14 @@ rb_spawn(int argc, const VALUE *argv)
* or contain meta characters:
*
* system('if true; then echo "Foo"; fi') # => true # Shell reserved word.
- * system('echo') # => true # Built-in.
+ * system('exit') # => true # Built-in.
* system('date > /tmp/date.tmp') # => true # Contains meta character.
* system('date > /nop/date.tmp') # => false
* system('date > /nop/date.tmp', exception: true) # Raises RuntimeError.
*
* Assigns the command's error status to $?:
*
- * system('echo') # => true # Built-in.
+ * system('exit') # => true # Built-in.
* $? # => #
* system('date > /nop/date.tmp') # => false
* $? # => #
@@ -4948,7 +4948,7 @@ rb_f_system(int argc, VALUE *argv, VALUE _)
*
* spawn('if true; then echo "Foo"; fi') # => 798847 # Shell reserved word.
* Process.wait # => 798847
- * spawn('echo') # => 798848 # Built-in.
+ * spawn('exit') # => 798848 # Built-in.
* Process.wait # => 798848
* spawn('date > /tmp/date.tmp') # => 798879 # Contains meta character.
* Process.wait # => 798849
@@ -8848,7 +8848,7 @@ proc_warmup(VALUE _)
* or contain meta characters:
*
* system('if true; then echo "Foo"; fi') # => true # Shell reserved word.
- * system('echo') # => true # Built-in.
+ * system('exit') # => true # Built-in.
* system('date > /tmp/date.tmp') # => true # Contains meta character.
* system('date > /nop/date.tmp') # => false
* system('date > /nop/date.tmp', exception: true) # Raises RuntimeError.