#!/bin/sh

set -eu
set -m  # enable background jobs

readonly SESSION=example-background-job
readonly MAINW=1


if tmux has-session -t "${SESSION}" 2>/dev/null; then
    tmux kill-session -t "${SESSION}"
fi

tmux new-session -s "${SESSION}" -d -n "${MAINW}"
tmux switch-client -t "${SESSION}"


temp_script="$(mktemp)"
readonly temp_script
cat > "${temp_script}" << EOF
#!/bin/sh

cleanup() {
    rm \$0  # remove self after exit
}

trap cleanup EXIT

sleep 3
tmux send-keys -t "${SESSION}:${MAINW}.1" 'echo hello' Enter
sleep 3
tmux kill-session -t "${SESSION}"
EOF

chmod +x "${temp_script}"
nohup "${temp_script}" >/dev/null &  # run in background