diff --git a/bin/sh/sh.1 b/bin/sh/sh.1
--- a/bin/sh/sh.1
+++ b/bin/sh/sh.1
@@ -2359,27 +2359,58 @@
 .It Ic getopts Ar optstring var
 The POSIX
 .Ic getopts
-command.
-The
-.Ic getopts
-command deprecates the older
-.Xr getopt 1
-command.
-The first argument should be a series of letters, each possibly
+command parses command-line options and arguments.
+The first argument
+.Va optstring
+should be a series of letters, each possibly
 followed by a colon which indicates that the option takes an argument.
-The specified variable is set to the parsed option.
+The specified variable
+.Va var
+is set to the parsed option.
 The index of
 the next argument is placed into the shell variable
 .Va OPTIND .
 If an option takes an argument, it is placed into the shell variable
 .Va OPTARG .
-If an invalid option is encountered,
+.Pp
+If the first character of
+.Va optstring
+is not a colon
+and if an invalid option (unspecified or missing a required argument) is encountered,
+.Va OPTARG
+is unset,
+.Ar var
+is set to
+.Ql \&?
+and a diagnostic message is written to stderr.
+.Pp
+If
+.Va optstring
+does start with a colon, invalid options give slightly different results:
+.Bl -enum -offset indent
+.It
+.Va OPTARG
+is set to the the option character found,
+.It
 .Ar var
 is set to
-.Ql \&? .
-It returns a false value (1) when it encounters the end of the options.
+.Ql \&:
+when a required argument is missing or to
+.Ql \&?
+when the option was not specified,
+.It
+no diagnostic message is written to stderr.
+.El
+.Pp
+.Ic getopts
+returns a false value (1) when it encounters the end of the options.
 A new set of arguments may be parsed by assigning
 .Li OPTIND=1 .
+The
+.Ic getopts
+command deprecates the older
+.Xr getopt 1
+command.
 .It Ic hash Oo Fl rv Oc Op Ar command ...
 The shell maintains a hash table which remembers the locations of commands.
 With no arguments whatsoever, the