tar and netcat

 

stdin and stdout with tar

While archiving, we can specify stdout as the output file so another command in a pipe can read it as stdin and process the archive.

This technique will transfer data through a Secure Shell (SSH) connection, for example:

    $ tar cvf - files/ | ssh user@example.com "tar xv -C Documents/"

In the preceding example, the files/directory is added to a tar archive which is output to stdout (denoted by -) and extracted to the Documents folder on the remote system.

Receiving server(open port 44023)

root@Receiver:/StoragePool/data/logs/Firewalls/2020/11# nc -l 44023 | pv | tar x

2.27GiB 0:01:16 [46.6MiB/s] [                                                                                                                                         <=>                   ]

Sending server (send dir named 12 to 22)

root@Sender:/opt/immune/storage/logs/Firewalls/2020/11# ls

01  02  03  04  05  06  07  08  09  10  11  12  13  14  15  16  17  18  19  20  21  22

root@Sender:/opt/immune/storage/logs/Firewalls/2020/11# tar cf - 13  14  15  16  17  18  19  20  21 | nc 172.16.104.39 44023 

The sender server should run the following command


$ tar cf - logs/ | netcat 192.168.0.1 9000

and the receiveing server should listen with with this command

$ netcat -l -p 9000 | tar x