I'm trying to write a shell script over ssh via a bash prompt. The shell, however, insists on interpreting any variable I want to write instead of writing it directly to file. For example, cat <<EOF >checkup.sh\n'$command'EOF is simply written as '' to file. How do I get $command written instead? I've tried every practical method of escaping I can think of.

If it changes anything, I'm doing it over PHP using phpseclib.