我想知道使用-r选项创建帐户的含义是什么？
# useradd -r ...
帮助说：
-r, --system
Create a system account.
System users will be created with no aging information in /etc/shadow, and their
numeric identifiers are chosen in the SYS_UID_MIN-SYS_UID_MAX range, defined in
/etc/login.defs, instead of UID_MIN-UID_MAX (and their GID counterparts for the
creation of groups).
Note that useradd will not create a home directory for such an user, regardless
of the default setting in /etc/login.defs (CREATE_HOME). You have to specify the
-m options if you …