uidmin = 1000
uidmax = 60000
gidmin = 1000
gidmax = 60000
for line in open('/etc/login.defs').read().split('\n'):
     try:
         line = line[:line.index('#')]
     except ValueError:
         pass
     keyval = line.split()
     if len(keyval) < 2:
         continue 
     if keyval[0] == 'UID_MIN':
         uidmin = int(keyval[1])
     if keyval[0] == 'UID_MAX':
         uidmax = int(keyval[1])
     if keyval[0] == 'GID_MIN':
         gidmin = int(keyval[1])
     if keyval[0] == 'GID_MAX':
         gidmax = int(keyval[1])

def show_passwd(shadowmode=False):
    for line in open('/etc/passwd').read().split('\n'):
        try:
            user, _, uid, _ = line.split(':', 3)
        except ValueError:
            continue
        uid = int(uid)
        if uid >= uidmin and uid <= uidmax:
            if shadowmode:
                yield '{0}:!!:::::::'.format(user)
            else:
                yield line

def show_group(shadowmode=False):
    for line in open('/etc/group').read().split('\n'):
        try:
            _, _, gid, _ = line.split(':', 3)
        except ValueError:
            continue
        gid = int(gid)
        if gid >= gidmin and gid <= gidmax:
            yield line


if __name__ == '__main__':
    if 'passwd' in sys.argv[1]:
        for line in show_passwd():
            print(line)
    elif 'shadow' in sys.argv[1]:
        for line in show_passwd(True):
            print(line)
    elif 'group' in sys.argv[1]:
        for line in show_group():
            print(line)