I have a script /etc/init.d/script.sh configured with update-rc.d to run on startup, which it does ok.  It contains line:python pathto/script.py >> /home/sd/log.txt 2>&1The script runs fine but its output isn't recorded as intended, which is in a symlink folder linking to an SD card.  The line does output as intended when executed manually.  Any idea how to get update-rc.d to behave?
update-rc.d process output to symlink file
symlink
It sounds like the SD card is not mounted at the time that your init.d script is run.If that's the case, make sure that it is mounted (e.g. by mounting the SD card in the script, or by changing the priority of your script with update-rc.d so that it runs after the mount).