solaris - vipw (1)

     vipw - edit the password file

     /usr/ucb/vipw

     SUNWscpu

     vipw edits the password file while setting  the  appropriate
     locks,  and does any necessary processing after the password
     file is unlocked.  If the password  file  is  already  being
     edited, then you will be told to try again later.  The vi(1)
     editor will be used unless the environment  variable  VISUAL
     or EDITOR indicates an alternate editor.

     vipw performs a number of consistency checks on the password
     entry  for  root,  and will not allow a password file with a
     "mangled" root entry to be installed.  It  also  checks  the
     /etc/shells file to verify the login shell for root.

     /etc/ptmp
     /etc/shells

     passwd(1), vi(1), passwd(4)