Linux- How to: Edit password, group

user vipw command for the purpose. man page listing is below. vipw is system command

VIPW(8)                                                  System Management Commands                                                  VIPW(8)

NAME
       vipw, vigr - edit the password, group, shadow-password or shadow-group file

SYNOPSIS
       vipw [options]

       vigr [options]

DESCRIPTION
       The vipw and vigr commands edits the files /etc/passwd and /etc/group, respectively. With the -s flag, they will edit the shadow
       versions of those files, /etc/shadow and /etc/gshadow, respectively. The programs will set the appropriate locks to prevent file
       corruption. When looking for an editor, the programs will first try the environment variable $VISUAL, then the environment variable
       $EDITOR, and finally the default editor, vi(1).

OPTIONS
       The options which apply to the vipw and vigr commands are:

       -g, --group
           Edit group database.

       -h, --help
           Display help message and exit.

       -p, --passwd
           Edit passwd database.

       -q, --quiet
           Quiet mode.

       -s, --shadow
           Edit shadow or gshadow database.

ENVIRONMENT
       VISUAL
           Editor to be used.

       EDITOR
           Editor to be used if VISUAL is not setENVIRONMENT
       VISUAL
           Editor to be used.

       EDITOR
           Editor to be used if VISUAL is not set.

FILES
       /etc/group
           Group account information.

       /etc/gshadow
           Secure group account information.

       /etc/passwd
           User account information.

       /etc/shadow
           Secure user account information.

SEE ALSO
       vi(1), group(5), gshadow(5) , passwd(5), , shadow(5).