On Linux, if you want to attach a detachable session (similar to screen) to a currently running command without using screen, you can use the reptyr tool. This allows you to move an existing process to a new terminal or a screen/tmux session.

Steps to Attach a Detachable Session to a Running Command

1. Install reptyr

If not already installed, you can install it using your package manager:

• Debian/Ubuntu:
  bash

  Copy

  sudo apt install reptyr

• RHEL/CentOS:
  bash

  Copy

  sudo yum install reptyr

• Arch Linux:
  bash

  Copy

  sudo pacman -S reptyr

2. Find the PID of the Running Command

Use ps or pgrep to find the Process ID (PID) of the command you want to attach:

ps aux | grep "your_command"

or

pgrep -f "your_command"

3. Attach the Process to a New Terminal

Open a new terminal and run:

reptyr <PID>

This will move the process to the new terminal, allowing you to interact with it.

4. (Optional) Use tmux for Detachable Sessions

If you want a detachable session (like screen), you can:

1. Start a tmux session:
   bash

   Copy

   tmux new -s mysession

2. Inside tmux, run:
   bash

   Copy

   reptyr <PID>

3. Detach from tmux with Ctrl+B D and reattach later with:
   bash

   Copy

   tmux attach -t mysession

Alternative: Use disown to Keep a Process Running

If you just want to detach a process from the current terminal (but not attach it to a new one), you can use:

disown -h %1

(Replace %1 with the job number from jobs.)

Key Notes

• reptyr requires root privileges for some processes.
• If the process is already in the background, you may need to bring it to the foreground first (fg).
• Works best with single-process commands (not complex shells or scripts).

Would you like help with a specific use case?