Avoid $(git_ps) for NFS mounted directory

bashrc_no_gitps_for_nfs.sh

export NFS_MOUNT_PATH="$HOME/titan" # colon-separated list
export BACKUP_PS1=
function avoid_gitps_on_nfs() {
    IFS=":"
    set $NFS_MOUNT_PATH
    for var in $NFS_MOUNT_PATH; do
        if [ -n "`echo \"^$PWD\" | grep -e $var`" ]; then
            export BACKUP_PS1=$PS1
            export PS1=$NFS_PS1
            return
        fi
    done
    if [ -n "$BACKUP_PS1" ]; then
        export PS1=$BACKUP_PS1
    fi
}

function cd() {
    builtin cd $@ && avoid_gitps_on_nfs
}