From 7c862eac22b81a8224a9b9c549bb2eebb3f77b7f Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@mengyan1223.wang>
Date: Mon, 2 May 2022 16:02:10 +0800
Subject: GID 5 (for tty) is also special

---
 chapter07/createfiles.xml | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/chapter07/createfiles.xml b/chapter07/createfiles.xml
index 71cb39c1f..eda30ed2e 100644
--- a/chapter07/createfiles.xml
+++ b/chapter07/createfiles.xml
@@ -165,9 +165,14 @@ EOF</userinput></screen>
   url="http://refspecs.linuxfoundation.org/lsb.shtml"/>) only recommends that,
   besides the group <systemitem class="groupname">root</systemitem> with a
   Group ID (GID) of 0, a group <systemitem class="groupname">bin</systemitem>
-  with a GID of 1 be present. All other group names and GIDs can be chosen
-  freely by the system administrator since well-written programs do not depend
-  on GID numbers, but rather use the group's name.</para>
+  with a GID of 1 be present. The GID of 5 is widely used for
+  <systemitem class="groupname">tty</systemitem> group, and the number 5 is
+  also used in <phrase revision="systemd">systemd</phrase>
+  <phrase revision="sysv"><filename>/etc/fstab</filename></phrase> for the
+  <systemitem class="filesystem">devpts</systemitem> filesystem.
+  All other group names and GIDs can be chosen freely by the system
+  administrator since well-written programs do not depend on GID numbers,
+  but rather use the group's name.</para>
 
   <para>The ID 65534 is used by the kernel for NFS and separate user
   namespaces for unmapped users and groups (those exist on the NFS server
-- 
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