Shell

Handy Shell Commands for Beginners

Check if a file exists if [ ! -f "/home/pi/test.sh" ]; then echo "file exists" fi Check if a directory exists if [ -d "/home/pi/test" ]; then echo "test dir exists" fi Install Apt-Get Package # update pip # check if package is installed # install package if not installed installPackage() { retval=0 echo "Installing package $1" if [ $(dpkg-query -W -f='${Status}' $1 2>/dev/null | grep -c "ok installed") -eq 0 ]; then echo "Package $1 is not installed" if echo "yes" | sudo apt-get install $1; then retval=1 fi else echo "Package $1 is already installed" retval=1 fi return "$retval" } Manually Set Date Time sudo date -s '2019-05-10 09:07:00' Setup SSH Keys mkdir -p /home/pi/.