diff --git a/doc/src/sgml/ref/initdb.sgml b/doc/src/sgml/ref/initdb.sgml
index 74008a9a82f..bdd613e77ff 100644
--- a/doc/src/sgml/ref/initdb.sgml
+++ b/doc/src/sgml/ref/initdb.sgml
@@ -525,6 +525,18 @@ PostgreSQL documentation
       </listitem>
      </varlistentry>
 
+     <varlistentry id="app-initdb-option-show">
+      <term><option>-s</option></term>
+      <term><option>--show</option></term>
+      <listitem>
+       <para>
+        Show internal settings and exit, without doing anything else.  This
+        can be used to debug the <application>initdb</application>
+        installation.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="app-initdb-option-sync-method">
       <term><option>--sync-method=<replaceable>method</replaceable></option></term>
       <listitem>
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 12ae194067f..f00718a0150 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -2481,7 +2481,7 @@ usage(const char *progname)
 	printf(_("  -n, --no-clean            do not clean up after errors\n"));
 	printf(_("  -N, --no-sync             do not wait for changes to be written safely to disk\n"));
 	printf(_("      --no-instructions     do not print instructions for next steps\n"));
-	printf(_("  -s, --show                show internal settings\n"));
+	printf(_("  -s, --show                show internal settings, then exit\n"));
 	printf(_("      --sync-method=METHOD  set method for syncing files to disk\n"));
 	printf(_("  -S, --sync-only           only sync database files to disk, then exit\n"));
 	printf(_("\nOther options:\n"));