We've all been there - you're running a long compile job or database migration through SSH when suddenly your connection drops. The process keeps running server-side, but you've lost visibility. Here's how to regain control without restarting your work.

The most robust approach is using terminal multiplexers. Here's how to set up tmux:

# First install tmux if needed
sudo apt-get install tmux  # Debian/Ubuntu
sudo yum install tmux      # CentOS/RHEL

# Start a named session
tmux new -s mysession

# Detach from session (Ctrl+b then d)
# Later, reattach from any connection:
tmux attach -t mysession

For older systems where tmux isn't available, GNU screen works similarly:

screen -S sessionname
# Detach with Ctrl+a then d
# Reattach with:
screen -r sessionname

For quick reconnection attempts without multiplexers:

# During initial SSH connection:
ssh -o ServerAliveInterval=60 user@host

# If dropped, check for hanging processes with:
ps aux | grep your_process

Create a resilient SSH wrapper script:

#!/bin/bash
while true; do
    ssh -o TCPKeepAlive=yes -o ServerAliveInterval=15 user@host
    sleep 5
    echo "Reconnecting..."
done

If you need to check on processes without reattaching:

# Find your process ID
ps aux | grep process_name

# Check process status
cat /proc/PID/status

# View output if writing to file
tail -f /path/to/output.log

When working with long-running processes over SSH, sudden disconnections can be frustrating. Linux systems provide several ways to maintain and restore sessions:

# Check if your SSH server supports TCPKeepAlive
ssh -o TCPKeepAlive=yes user@host

The most robust solution is using tmux before starting your process:

# Install tmux if not present
sudo apt-get install tmux  # Debian/Ubuntu
sudo yum install tmux      # CentOS/RHEL

# Basic workflow:
tmux new -s mysession      # Start new session
./long_running_script.sh   # Run your process
# Detach with Ctrl-b d

# After reconnection:
tmux attach -t mysession

For older systems where tmux isn't available:

screen -S mysession
./my_process
# Detach with Ctrl-a d

# Reattach later:
screen -r mysession

If you didn't use session management tools:

# Find your process
ps aux | grep process_name

# Check for running shells
who -a
w

Add these to ~/.ssh/config:

Host *
    ServerAliveInterval 60
    ServerAliveCountMax 5
    TCPKeepAlive yes
    ControlMaster auto
    ControlPath ~/.ssh/control:%h:%p:%r
    ControlPersist 1h

For processes running in nohup:

# Check output if redirected
tail -f nohup.out

# Reattach to existing process if possible
reptyr $(pidof your_process)

Always consider:

• Running important processes with nohup
• Redirecting output to log files
• Using systemd services for critical processes

nohup ./script.sh > output.log 2>&1 &