File Transfer Through Terminal

Sometimes one connects to a terminal through SSH and using SCP / rsync isn't an available option.

I use ssh a lot to connect to remote computers. Sometimes I have to connect to a computer that's hidden, so I ssh into a jump host and ssh again into the destination. While poking around, I may have the urge to download a file to my computer, but that's not usually easy to do.


  • Unable to copy a file directly from one machine to another even though you are connected through an interactive session, probably through ssh or another terminal.
  • User may copy a file to the intermediate host and then separately copy the file to the destination host, but that means the file temporarily is on the intermediate computer. It also is more work.


  • Most terminal emulators do not have file transfer abilities built-in through a side data stream.


The easiest thing to do is to employ additional software on one side or the other. Slightly harder solutions are also presented. All of these work.

With luck, problem solved.


This software was used to transfer files over modems, yet is still readily available in package managers. Plus, screen has ZModem support built in.

  1. Run screen.
  2. SSH to any remote server.
  3. Type Control-a and :, then you will get the screen command prompt.
  4. Type zmodem capture.
  5. Install lrzsz on the remote server.

Now you can use sz to send a file to your local computer or rz to receive one. screen will prompt you with a command when it detects the remote computer is using ZModem.

You should use ssh -e none to disable sequences like ~., which ZModem does not encode.

If you prefer to avoid screen, you could use zssh to initiate the SSH connection and it will trigger the zmodem commands automatically, just like how screen works.

Base64 Encoding

The coreutils package includes base64, which encodes any file. The opposite is base64 --decode.

  1. SSH to any remote server.
  2. Capture traffic to a log file. This must be supported by your terminal emulator.
  3. Run base64 my-file to get the encoded file.

There are alternate encoding methods available, such as uuencode and xxencode as well. Each has their own advantages.

Port Forwarding

This exposes the SSH port through the intermediate computer.

  1. Use ssh -L 8022:real-destination-computer:22 user@intermediate-computer to kick off your SSH session. This also opens port 8022 on your computer. When you connect to that port, it would be a direct connection to the destination.
  2. Copy files by specifying the port using scp -P 8022 my-file localhost:.

This solution can still work through multiple relays by exposing a port and repeatedly forwarding it.