Linux useradd --添加用户账号

用途说明
添加用户，与useradd是同一命令。需要root权限才能执行（有root權限）。
常用参数
-d home_dir设定使用者的主目录为 home_dir
-p passwd 指定用户的登录密码。RHEL4支持此参数，RHEL5已经去掉这个参数了。
-g group 指定用户所在的群组。
使用示例
示例一
[root@localhostroot]#adduser xxx

[root@localhostroot]#ls -l /home/xxx

total 0
[root@localhostroot]#ls -ld /home/xxx

drwx------ 2 xxx xxx 4096 9月 29 16:05/home/xxx
[root@localhostroot]#grep xxx /etc/passwd /etc/shadow /etc/group
/etc/passwd:xxx:x:500:500::/home/xxx:/bin/bash
/etc/shadow:xxx:!!:14881:0:99999:7:::
/etc/group:xxx:x:500:
[root@localhostroot]#
[root@localhostroot]#ssh xxx@localhost

xxx@localhost'spassword:
Permission denied,please try again.
xxx@localhost'spassword:
Permission denied,please try again.
xxx@localhost'spassword:
Permission denied(publickey,password,keyboard-interactive).
[root@localhostroot]#
[root@localhostroot]#
[root@localhostroot]#passwd xxx

Changing passwordfor user xxx.
New password:
BAD PASSWORD: it istoo simplistic/systematic
Retype new password:
passwd: allauthentication tokens updated successfully.
[root@localhostroot]#
[root@localhostroot]#
[root@localhostroot]#ssh xxx@localhost

xxx@localhost'spassword:
[xxx@localhost xxx]$
示例二
[root@localhostroot]#adduser -d /opt/oracle oracle

[root@localhostroot]#ls -ld /opt/oracle

drwx------ 2 oracle oracle 1024 9月 29 16:10/opt/oracle
[root@localhostroot]#grep oracle /etc/passwd /etc/shadow /etc/group
/etc/passwd:oracle:x:501:501::/opt/oracle:/bin/bash
/etc/shadow:oracle:!!:14881:0:99999:7:::
/etc/group:oracle:x:501:
[root@localhostroot]#