autoupdate.sh

#!/bin/sh

FILENAME='check_update.sh'
URL='https://raw.github.com/gist/1950778'

if [[ -f $FILENAME ]]; then
	echo 'Updating file in place...'
	curl --retry 3 --progress-bar --location --time-cond $FILENAME --remote-time --output $FILENAME $URL
else
	echo 'File does not exist, downloading...'
	curl --retry 3 --progress-bar --remote-time --location --output $FILENAME $URL
	chmod +x $FILENAME
fi

./$FILENAME