Script to alert you upon login if your diskspace percentage space is >= 80%.

Edit your .bashrc:

    $ vi ~/.bashrc

Insert this script at the end of the file

    # Check Diskspace
    ALERT=80
    df -H | grep -vE '^Filesystem' | awk '{ print $5 " " $1 " " $6 }' | while read output;
    do
      #echo $output
      usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1  )
      partition=$(echo $output | awk '{ print $2 }' )
      mount=$(echo $output | awk '{ print $3 }' )
      if [ $usep -ge $ALERT ]; then
        echo "Running out of space \"$partition ($usep%)\" on \"$mount\""
      fi
    done

Save and exit.