:Keep processes running on Linux after an SSH disconnect

Choose a solution

To keep a command running after your SSH session closes, choose one of the following solutions:

• Solution 1: Use the nohup and & commands: Best for running one-time, non-interactive automated scripts or commands.

• Solution 2: Use GNU screen: Best for long-running, interactive tasks that may require debugging or be resumed later.

Solution 1: Use the nohup and & commands

The nohup command lets a process continue running after you close the terminal, and the & symbol sends the process to the background.

1. Run the command in the background.

   This command redirects both output and error to [your_log_file].

   sudo nohup [your_command] >[your_log_file] 2>&1 &

   For example, to run bash hello.sh in the background and write the output to a new file named output.log in the current directory, run the following command: sudo nohup bash hello.sh > output.log 2>&1 &.

2. View the command output.

   sudo tail -f [your_log_file]

3. End the process.

   Important

   Terminating the process ends the command or task. Proceed with caution.

   1. Find the Process ID (PID). Replace [your_command] with the command you ran in Step 1.

      sudo ps aux | grep "[your_command]"

      For example, if you ran sudo nohup bash hello.sh > output.log 2>&1 &, you would run sudo ps aux | grep "bash hello.sh" to find its PID.

   2. Use the sudo kill [PID] command to terminate the process.

Solution 2: Use GNU screen

1. Install GNU screen.

   • For Alibaba Cloud Linux and CentOS

     sudo yum install -y screen

   • For Debian and Ubuntu

     sudo apt-get install -y screen

2. Create and enter a new session.

   [Name] is a custom name for your session.

   screen -S [Name]

   For example, to create a session named mysession, run sudo screen -S mysession.

3. Run your task in the new session.

4. Detach the session.

   Press Ctrl+A+D to detach the current screen session.

5. Resume the session.

   1. List the available screen sessions to find the target session's PID.

      sudo screen -ls

      There is a screen on:
              2046.mytask     (Detached)
      1 Socket in /run/screen/S-root.

      In this example, the session PID is 2046.

   2. Resume the session.

      Replace [PID] with the session PID from the previous step.

      sudo screen -r -d [PID]

      For example, to resume the session with a PID of 2046, run sudo screen -r -d 2046.

6. Terminate the session.

   Important

   Terminating a session also ends all tasks and commands running within it. Proceed with caution

   Replace [PID] with session's PID.

   sudo kill [PID]