FreeBSD : добавить пользователя в группу

PW(8)                   FreeBSD System Manager's Manual                  PW(8)

NAME
     pw — create, remove, modify & display system users and groups

SYNOPSIS
     pw [-V etcdir] useradd [name|uid] [-C config] [-q] [-n name] [-u uid]
        [-c comment] [-d dir] [-e date] [-p date] [-g group] [-G grouplist]
        [-m] [-M mode] [-k dir] [-w method] [-s shell] [-o] [-L class]
        [-h fd | -H fd] [-N] [-P] [-Y]
     pw [-V etcdir] useradd [name|uid] -D [-C config] [-q] [-b dir] [-e days]
        [-p days] [-g group] [-G grouplist] [-k dir] [-M mode] [-u min,max]
        [-i min,max] [-w method] [-s shell] [-y path]
     pw [-V etcdir] userdel [name|uid] [-n name] [-u uid] [-r] [-Y]
     pw [-V etcdir] usermod [name|uid] [-C config] [-q] [-n name] [-u uid]
        [-c comment] [-d dir] [-e date] [-p date] [-g group] [-G grouplist]
        [-l name] [-m] [-M mode] [-k dir] [-w method] [-s shell] [-L class]
        [-h fd | -H fd] [-N] [-P] [-Y]
     pw [-V etcdir] usershow [name|uid] [-n name] [-u uid] [-F] [-P] [-7] [-a]
     pw [-V etcdir] usernext [-C config] [-q]
     pw [-V etcdir] groupadd [group|gid] [-C config] [-q] [-n group] [-g gid]
        [-M members] [-o] [-h fd | -H fd] [-N] [-P] [-Y]
     pw [-V etcdir] groupdel [group|gid] [-n name] [-g gid] [-Y]
     pw [-V etcdir] groupmod [group|gid] [-C config] [-q] [-n name] [-g gid]
        [-l name] [-M members] [-m newmembers] [-d oldmembers] [-h fd | -H fd]
        [-N] [-P] [-Y]
     pw [-V etcdir] groupshow [group|gid] [-n name] [-g gid] [-F] [-P] [-a]
     pw [-V etcdir] groupnext [-C config] [-q]
     pw [-V etcdir] lock [name|uid] [-C config] [-q]
     pw [-V etcdir] unlock [name|uid] [-C config] [-q]

DESCRIPTION
     The pw utility is a command-line based editor for the system user and
     group files, allowing the superuser an easy to use and standardized way
     of adding, modifying and removing users and groups.  Note that pw only
     operates on the local user and group files.  NIS users and groups must be
     maintained on the NIS server.  The pw utility handles updating the
     passwd, master.passwd, group and the secure and insecure password data‐
     base files, and must be run as root.

     The first one or two keywords provided to pw on the command line provide
     the context for the remainder of the arguments.  The keywords user and
     group may be combined with add, del, mod, show, or next in any order.
     (For example, showuser, usershow, show user, and user show all mean the
     same thing.)  This flexibility is useful for interactive scripts calling
     pw for user and group database manipulation.  Following these keywords,
     you may optionally specify the user or group name or numeric id as an
     alternative to using the -n name, -u uid, -g gid options.

...