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CHAGE command in LINUX

CHAGE - the command is used to change/show user's password related information like when it will expire, when it must be changed, when user should be warned to change the password etc.

FORMAT:
For root users:      

chage [-D binddn] [-P path] [-m mindays]
             [-M maxdays] [-d lastday] [-I inactive] [-E expiredate] [-W warndays] user

For normal user      

chage -l [user]


DESCRIPTION

  • chage  is  used  to  list and change the password expiry information of a user. It allows the system administrator to change the number of days between allowed and required password changes and the date of the last password change. 
  • It allows  also  to  define  when  an  account will expire.

chage -E 2016-03-31 student1

 

chage1

 

  • CHAGE command is mostly an administrative level command. Besides a normal user can only list the password related information for himself/herself using -l option.
  • If no option is given, chage operates in an interactive mode, prompting the user with the current values for  all  of the  fields.
  • You can enter new value or leave the line blank to use the  current value.
  • If the users exists in the local passwd file, but not in the local shadow file, chage will create a new entry in the shadow  file.

 

Following are the options availabe for CHAGE:
 -l, --list

  • This option will list the password expiry information in a human readable format.
  • The user will see the date when he changed the password the last time, when the password will be expire, when the password will be locked and when the account will expire.

-m, --mindays mindays
 

  • With this option the minimum number of days between password changes is changed.
  • A value of zero for this field indicates that the user may change her password at any time. Else the user will not be permitted to change the password until min days have elapsed.

 


#>chage -m 0 student1
Only an administrator is allowed to change aging information.

Note: You have to a root user to execute chage command except for listing (chage -l <user>).  

   

chage3 

 

-M, --maxdays maxdays
              With  this  option  the  maximum number of days during which a password is valid is changed. When maxdays plus lastday is less than the current day, the user will be required to change his password before  being  able  to use the account.

  -d, --lastday lastday
              With  this  option  the date when the password was last changed can be set to another value. lastday has to be specified as number of days since January 1st, 1970. The date may also be expressed in the format  YYYY-MM-DD.
              If supported by the system, a value of zero forces the user to change the password at next login.

 

chage4
 

-W, --warndays warndays
              With this option the number of days of warning before a password change  is  required  can  be  changed.  This option  is  the number of days prior to the password expiring that a user will be warned the password is about to expire.

 

chage2

 

 -I, --inactive inactive
              This option is used to set the number of days of inactivity after a password has expired before the account is locked.  A  user  whose  account is locked must contact the system  administrator before being able to use the account again.  A value of -1 disables this feature.


 

-P --path path

  •  Using this option we can ask chage to use another password files instead of regular /etc/passwd /etc/shadow files.
  •  This is useful for example on NIS master servers, where you do not want to give all users in the NIS database automatic access to your NIS server and the NIS map is build from special files.
 
 

Category: Open System-Linux | Views: 1130 | Added by: shanky | Tags: how to change password inoformation, unix, user password, linux, /etc/passwd, chage, Password, change password | Rating: 0.0/0

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