Linux 命令整理 —— 用户管理

Linux用户管理以读、写、执行动作为权限，以用户组为单位，限制用户行为。对于文件的的操作，可以限制读、写、执行中的哪一种，也可以限制文件所有者、组用户、组外用户相应的权限。 

所以，要建立用户，最好先确定其所在的组。 
一、用户组操作 
1. 创建用户组——groupadd 

#新增deploy组  
groupadd deploy

2. 修改用户组——groupmod 

#将用户组deploy更名为deploy1  
groupmod -n deploy1 deploy  

注意是将已存在的deploy组更名为deploy1 

3. 删除用户组——groupdel 

#删除用户组deploy1  
groupdel deploy1

4. 查看用户组——groups /etc/group 
groups只能查看当前用户所在的组，以下是root用户所在的组。 

引用

# groups 
root bin daemon sys adm disk wheel

要看所有用户组信息，直接查看/etc/group： 

引用

# cat /etc/group 
root:x:0:root 
bin:x:1:root,bin,daemon 
daemon:x:2:root,bin,daemon 
sys:x:3:root,bin,adm 

二、用户操作 
1. 创建用户——useradd 

引用

# useradd 
Usage: useradd [options] LOGIN 

Options: 
  -b, --base-dir BASE_DIR       base directory for the new user account 
                                home directory 
  -c, --comment COMMENT         set the GECOS field for the new user account 
  -d, --home-dir HOME_DIR       home directory for the new user account 
  -D, --defaults                print or save modified default useradd 
                                configuration 
  -e, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE 
  -f, --inactive INACTIVE       set password inactive after expiration 
                                to INACTIVE 
  -g, --gid GROUP               force use GROUP for the new user account 
  -G, --groups GROUPS           list of supplementary groups for the new 
                                user account 
  -h, --help                    display this help message and exit 
  -k, --skel SKEL_DIR           specify an alternative skel directory 
  -K, --key KEY=VALUE           overrides /etc/login.defs defaults 
  -m, --create-home             create home directory for the new user 
                                account 
  -l,                       do not add user to lastlog database file 
  -M,                       do not create user's home directory(overrides /etc/login.defs) 
  -r,                       create system account 
  -o, --non-unique              allow create user with duplicate 
                                (non-unique) UID 
  -p, --password PASSWORD       use encrypted password for the new user 
                                account 
  -s, --shell SHELL             the login shell for the new user account 
  -u, --uid UID                 force use the UID for the new user account 
  -Z, --selinux-user SEUSER     use a specific SEUSER for the SELinux user mapping 

新建用户deploy，位于deploy组，用于部署工作： 

#-g 组 用户  
useradd -g deploy deploy

新建用户nginx，位于www组，且不可登录，用于启动nginx： 

useradd -s /sbin/nologin -g www nginx

为用户deploy设置密码： 

引用

# passwd deploy 
Changing password for user deploy. 
New UNIX password: 
Retype new UNIX password: 
passwd: all authentication tokens updated successfully. 

新建用户test，位于www组，并为其设置密码为1234567890： 

useradd -g www -p 1234567890 test

2. 修改用户——usermod gpasswd 

引用

# usermod 
Usage: usermod [options] LOGIN 

Options: 
  -a, --append                  append the user to the supplemental GROUPS 
                                (use only with -G) 
  -c, --comment COMMENT         new value of the GECOS field 
  -d, --home HOME_DIR           new home directory for the user account 
  -e, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE 
  -f, --inactive INACTIVE       set password inactive after expiration 
                                to INACTIVE 
  -g, --gid GROUP               force use GROUP as new primary group 
  -G, --groups GROUPS           new list of supplementary GROUPS 
  -h, --help                    display this help message and exit 
  -l, --login NEW_LOGIN         new value of the login name 
  -L, --lock                    lock the user account 
  -m, --move-home               move contents of the home directory to the new 
                                location (use only with -d) 
  -o, --non-unique              allow using duplicate (non-unique) UID 
  -p, --password PASSWORD       use encrypted password for the new password 
  -s, --shell SHELL             new login shell for the user account 
  -u, --uid UID                 new UID for the user account 
  -U, --unlock                  unlock the user account 
  -Z, --selinux-user    new selinux user mapping for the user account 

将用户test登录目录设为/home/test，并将其添加到www组： 

usermod -d /home/test -G www test

将用户test追加到deploy组： 

usermod -a -G deploy test

注意：如果没有-a，将直接变更用户所在组，即将用户从原所在组中移除！ 

这时候用gpasswd就比较安全一些！

gpasswd -a test deploy

将用户test从www组中移除： 

gpasswd -d test www

3. 删除用户——userdel 
删除用户test，并移除其登录目录： 

　　　　

　userdel -r test