Go back in directory tree

za.sh

function za()
{
## I added this in my bashrc so that I can easily
## jump back in my directory tree.
## There's probably a better way of doing this.
## But I was bored anyway.
## Backstory: https://chanux.wordpress.com/2012/08/09/no-more-cd-dot-dot-slash/
## See it in my bashrc: https://github.com/chanux/dotfiles/blob/master/bash/aliases#L25

## Usage: za <number>
##    Ex: za 2 (this will take you two directories up 
##               from your current working directory.
##               You can't go beyond your home directory.)
## To jump forward: https://github.com/rupa/z
 
    ZA_OLD_IFS=$IFS
    IFS=$(echo -en "\n\b")

    if [ -z $1 ];then
        za_mark=1
    else
        za_mark=$1
    fi

    za_dir=$PWD

    # When in home, do nothing
    [ $za_dir == $HOME ] && return

    while [[ $za_mark -gt 0 && $za_dir != $HOME ]];do
        za_dir=${za_dir%/*}
        let za_mark-=1
    done

    cd $za_dir

    IFS=$ZA_OLD_IFS
}