When executing remote commands through SSH, developers often need persistent sessions that survive disconnections. The naive approach fails because screen requires a proper terminal allocation:

ssh user@remote "screen -dmS logs tail -f /var/log/messages"  # Won't work directly

GNU Screen demands a terminal for session management. SSH command mode (-c) doesn't allocate a PTY by default, causing the "Must be connected to a terminal" error. The solution involves forcing pseudo-terminal allocation.

Force pseudo-terminal allocation using SSH's -t flag combined with screen's detach options:

ssh -t user@remote "screen -S session_name -dm bash -c 'your_command; exec bash'"

Practical example for monitoring logs:

ssh -t admin@server01 "screen -S log_monitor -dm bash -c 'tail -f /var/log/nginx/access.log; exec bash'"

For complex scenarios requiring multiple commands:

ssh -t deploy@prod "screen -S deployment -dm bash -c '
  git pull origin master &&
  npm install &&
  systemctl restart myapp;
  exec bash'"

Later reconnection to verify and attach:

ssh -t user@remote "screen -r session_name"

List active sessions:

ssh user@remote "screen -ls"

Bash function for your .bashrc:

function ssh-screen() {
  if [ $# -lt 3 ]; then
    echo "Usage: ssh-screen user host session command"
    return 1
  fi
  ssh -t $1@$2 "screen -S $3 -dm bash -c '$4; exec bash'"
}

When administering remote servers, a common pain point emerges: how to execute long-running commands that persist after SSH disconnection. The naive approach fails:

ssh user@host screen "your_command"

This triggers the frustrating "Must be connected to a terminal" error because screen requires a proper TTY allocation.

Modern SSH clients provide the -t flag to force pseudo-terminal allocation:

ssh -t user@host screen -dmS session_name "your_command"

The flags breakdown:

-t: Forces pseudo-terminal allocation

-dmS: Starts screen in detached mode with session naming

For mission-critical deployments, consider this robust pattern:

ssh -t user@host <<'EOF'
screen -S maintenance -dm bash -c '
  while true; do
    your_script.sh >> /var/log/script_output.log 2>&1
    sleep 60
  done
'
EOF

To verify and manage your detached sessions:

# List all screen sessions
ssh user@host screen -list

# Attach to specific session
ssh -t user@host screen -r session_name

# Kill unwanted sessions
ssh user@host screen -X -S session_name quit

If you encounter "Cannot open your terminal" errors, force UTF-8 mode:

ssh -t user@host LC_ALL=en_US.UTF-8 screen -md command

For systems with strict environments, wrap in a shell:

ssh -t user@host "bash -lc 'screen -dmS session command'"