Linux account information display and implementation account security

I. Account information display

1.groups command

Use the groups command to display the group memberships for a specified user account.

[email protected] ~]# groups--help

usage:groups [OPTION] ... [USERNAME] ...

Print group memberships for each USERNAME or, if no USERNAME are specified, for

The current process (which, differ if the groups database has changed).

--help Display this Help and exit

--version output version information and exit

Report groups bugs to [email protected]

GNU coreutils Home page:

General help using GNU software:

For complete documentation, Run:info coreutils ' groups invocation

Example: See which group the user Zhang is a member of.

[email protected] ~]# groups Zhang

Zhang:zhang Zhangsan

[Email protected] ~]#

You can see that user Zhang is a user belonging to the Zhang Group and the Zhangsan group.

2.id command

Use the ID command to display the ID of the user and the GID of the group to which the user belongs.

[[email protected] ~]# ID--help

Usage:id [OPTION] ... [USERNAME]

Print User and group information for the specified USERNAME,

or (when USERNAME omitted) is the current user.

-a ignore, for compatibility and other versions

-Z,--context print only the security context of the current user

-G,--group print only the effective group ID

-G,--groups print all group IDs

-N,--name print a name instead of a number, For-ugg

-R,--real print the real ID instead of the effective ID, With-ugg

-U,--user print only the effective user ID

--help Display this Help and exit

--version output version information and exit

Without any OPTION, print some useful set of identified information.

Report ID bugs to [email protected]

GNU coreutils Home page:

General help using GNU software:

For complete documentation, RUN:INFO coreutils ' ID invocation '

[Email protected] ~]#

Example 1: Query user Zhang's UID, GID, and attribution group.

[[email protected] ~]# ID Zhang

uid=513 (Zhang) gid=513 (Zhang) groups=513 (Zhang), 501 (Zhangsan)

[Email protected] ~]#

User Zhang's UID is 513, the default group is Zhang, the default user group GID is 513, belonging to the Zhang and Zhangsan group.

Example 2: Displays the GID of the primary group that the user Zhang belongs to.

[Email protected] ~]# id-g Zhang

513

[Email protected] ~]#

Example 3: Displays the GID of the group that the user Zhang belongs to.

[Email protected] ~]# id-g Zhang

513 501

[Email protected] ~]#

You can see that the GID of the group that the user Zhang belongs to is 513 and 501.

Example 4: Displays the UID of the user Zhang.

[Email protected] ~]# id-u Zhang

513

[Email protected] ~]#

You can see that the UID of user Zhang is 513.

3.W command

Use the W command to query the user who is logged on to the current computer in detail.

Example 1: Displays the user details of the logged on current computer.

4.who command

Use the WHO command to display simple information about the user who is logged on to the current computer.

[email protected] ~]# who

Root pts/0 2015-01-14 04:35 (192.168.12.1)

[Email protected] ~]#

5.chage

In the Linux system, you can use the Chage command to manage the aging of the user's password, preventing the user password from being compromised for prolonged use, or being hacked by a hacker's password.

[Email protected] ~]# chage

usage:chage [Options] [LOGIN]

Options:

-D,--lastday Last_day set Date of last password change to Last_day

-E,--expiredate expire_date set account expiration DATE to Expire_date

-H,--help display this help message and exit

-I,--inactive inactive set password inactive after expiration to inactive

-L,--list Show account aging Information

-M,--mindays min_days set minimum number of days before password change to Min_days

-M,--maxdays Max_days set Maximim number of days before password change to Max_days

-W,--warndays warn_days set expiration warning days to Warn_days

[Email protected] ~]#

Example: Displays the user's current password invalid information.

[Email protected] ~]# chage-l Zhang

Last password Change:jan 13, 2015

Password Expires:never

Password Inactive:never

Account Expires:never

Minimum number of days between password change:0

Maximum number of days between password change:99999

Number of days of warning before password expires:7

[Email protected] ~]#

Display and secure account information for Linux account