Adding new users.

10 Adding new users.

Steps involved (usually automated).

• Determine login name, user ID (UID), group ID (GID) & netgroup (if using NIS or NIS+)
  
• Enter data in /etc/passwd file
  
• Assign password
  
• Set account parameters (e.g., password aging, account expiration, quotas)
  
• Create home directory
  
• Copy initialization files
  
• Set file ownerships and protections (use chown, chgrp, chmod commands)
  
• Add user to other facilities (quota system, aliases file)
  
• Perform other site-specific initialization tasks
  
• Test new account
  

10.1 Fields in the /etc/passwd file.

logname:passwd:uid:gid:user info:home:shell

10.2 Fields in the /etc/group file.

group:passwd:gid:members

10.3 Choosing passwords.

One of the best algorithms to use is to take two non-related words, separate them with a punctuation character, mix in some upper-case characters, and perhaps reverse one of the words. E.g.,

• DOg.tenT (mixed upper/lower case)
  
• t00l%p0nd (zeros instead of "O")
  
• p33l*BOARd (substitute numeric for alpha)
  
• tned-Pile (reversed first word)
  

10.4 Shell initialization files.

• C shell: .cshrc, .login, .logout, /etc/cshrc,/etc/cshrc.std
  
• Borne shell: .profile, /etc/profile,/etc/profile.std
  
• Skeleton files: in /usr/skel, /etc/skel, or/etc/security directories
  

10.5 Automating account creation.

• sysadm (System V)
  
• passmgmt (System V)
  
• useradd (System V.4)
  
• adduser, addgroup (Some BSD, OSF/1)
  
• SMIT (AIX)
  
• nu (NeXTStep)
  
• Public domain scripts
  

10.6 Disabling and/or removing user accounts.

• Remove or modify entry in /etc/passwd
  
• Remove entry in NIS/NIS+ maps
  
• Remove $HOME/.rhosts files
  
• Remove mail spool file
  
• Remove from mail aliases file
  
• Remove any cron or at jobs
  
• Remove directory
  

10.7 Related articles

"Developing Common Login Scripts," Dinah McNutt, Unix Review, December 1995, p73. (includes sample .profile file for the Korn shell)

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