Some Basic Linux Command .

Q : How to add group then user in linux . ?
Ans :
1: add group by using command groupadd
2: add a user into the group by   command  useradd  -G   . for adding a user in multiple group  just seperate user by  useradd -G,,  
3:  now add password to  user by command passwd
4:  ensure that user has been added to group use command id ,you will see information         of user id ,group id  .
5:  add a existing user to existing group 
         usermod -a -G
        -a option is used for adding user in supplementry group .

6  :  adding user  to  a derive .
        useradd  -d /directory   
          ->  this will add user to a directory .
      Now come to  password
       use command 
        password  
7: how to install .Net  in RHEL 7 .
 Ans  :  https://www.microsoft.com/net/core#redhat        


8: how to delete a user 
    userdel --remove

9: how to stop ftp(21) in linux server .

     iptables -A INPUT -p tcp --destination-port 21 -j DROP

10:  To check which port are active 
          netstat -tnlp

11: how to add  user and providing sftp permission with particular directory .
   a:   useradd -d /path
   b:   ask for password  :
       passwd
   c:  now if you want that only owner should have access of folder then  change ownership by
       mentioned command
       chown -R