useful bash customizations

added the following lines to the _cd completion function (almost at the top of the function) within the bash_completion file:

#catch custom numbered up directory option
if [[ $cur =~ ^\.\.[0-9]+$ ]]; then
    local back="../"
    local num=$(echo "$cur" | cut -f 3 -d ".");
    cur=""
    for ((l=1;l<=$num;l++)); do cur=$cur$back; done;
    _filedir -d
    return
fi

This if statement allows you to cd up a specific number of times using the following format:

cd ..3

The above will be converted to:

cd ../../../

when you press tab. You can then press to see the directories within that back directory and continue to tab complete.