USER ADMINISTRATION Files
——————-
/etc/passwd -> system users info
/etc/shadow
/etc/group
/etc/gshadow——–contains the shadowed information for group accounts.
/etc/login.defs —-same as /etc/default/security in HP UX
/etc/default/useradd– contains the default values for GROUP, HOME, INACTIVE=-1 EXPIRE= SHELL=/bin/bash SKEL=/etc/skel etc.
/etc/shells diff shells
/etc/skel/ ===== is a directory which contains all the files that are copied to a user’s home directory whenever a new user is created.
/var/log/wtmp
/var/log/lastlog=====stores user last login information.
/var/log/btmp
# useradd <user> -> create a new user
e.g.
[root@mann ~]# useradd testusr
# adduser <user> -^
# passwd <user> -> change password
eg.
[root@mann ~]# passwd testusr Changing password for user testusr. New password: BAD PASSWORD: it is too short BAD PASSWORD: is too simple Retype new password: passwd: all authentication tokens updated successfully.
# passwd -l -> lock the user
e.g.
[root@mann ~]# passwd -l testusr Locking password for user testusr. passwd: Success
# passwd -S -> short information about the status of the password for a given account.Ths commands displays whether account lockout or not
same as getprpw in HPUX
eg
passwd -S testusr testusr LK 2012-08-17 0 99999 7 -1 (Password locked.)
# passwd -uf -> will unlock the account password
[root@mann ~]# passwd -uf testusr Unlocking password for user testusr. passwd: Success
To recheck
[root@mann ~]# passwd -S testusr testusr PS 2012-08-17 0 99999 7 -1 (Password set, MD5 crypt.)
$ passwd
# userdel <user> -> delete user
e.g.
[root@mann ~]# userdel testusr
# userdel -r -> delete user and his home directory
# usermod -> modify user
# usermod -G
# groupadd -> create a new group
# groupdel -> delete group
# groupmod -> modify group
# lastlog-u
e.g.
[root@mann ~]# lastlog -u testus1 Username Port From Latest testus1 pts/3 192.168.0.40 Sat Aug 18 05:40:28 -0700 2012
# chfn -> change finger
e.g.
[root@mann ~]# chfn testus1 Changing finger information for testus1. Name []: Manmohan Mirkar Office []: Home Park Office Phone []: xxx-xxxxxx Home Phone []: 9819025476
Finger information changed.
[root@mann ~]# cat /etc/shadow|grep -i testus1 testus1:x:502:502:Manmohan Mirkar,Home Park,xxx-xxxxxxx,9819045476:/home/testus1:/bin/bash
# chsh -> change shell
# chage -d x change user password expiry information
e.g
[root@mann ~]# chage testus1 Changing the aging information for testus1 Enter the new value, or press ENTER for the default Minimum Password Age [0]: 0 Maximum Password Age [99999]: Last Password Change (YYYY-MM-DD) [2012-08-18]: Password Expiration Warning [7]: Password Inactive [-1]: Account Expiration Date (YYYY-MM-DD) [1969-12-31]:
$ ulimit Limit user resources
To set a soft limit on the maximum amount of memory available to a given process to a value that is less than the total amount of memory on the system on a system with 1 gig of real memory and 500 megs of virtual memory you would set the following values in /etc/profile:
ulimit -S -m 1000000
ulimit -S -v 500000
With this value set, the system will kill any process that tries to take up more resources than you have set as a limit.
# pwck -> check passwd and shadow files in /etc
# grpck -> check group and gshadow files in /etc
# pwconv -> enable password shadowing
# pwunconv -> disable password shadowing
# grpconv -> enable group shadowing
# grpunconv -> disable group shadowing
# su <username>
# su -l <username>
# su – <username>
# su –