Bash – Removing or Clearing Stack of popd/pushd Paths

This function should remove dups.

dedup(){
    declare -a new=() copy=("${DIRSTACK[@]:1}")
    declare -A seen
    local v i
    seen[$PWD]=1
    for v in "${copy[@]}"
    do if [ -z "${seen[$v]}" ]
       then new+=("$v")
            seen[$v]=1
       fi
    done
    dirs -c
    for ((i=${#new[@]}-1; i>=0; i--))
    do      builtin pushd -n "${new[i]}" >/dev/null
    done
}

It copies the list of dirs, except the first which is bogus, into an array copy, and for each dir adds it to a new array if we have not already seen it (an associative array). This ensures older dup entries, which are later in the array, are not copied. The dir list is cleared, and the array is then pushd in reverse order.

The first bogus element of the dirs list is the current directory, which is unchanged. It is set in the seen array at the start to also get it removed if earlier in the dir list.

If you want to do this automatically, you can override pushd eg:

pushd(){
    builtin pushd "$@"
    dedup
}

You may pre-populate the directory stack in your ~/.bashrc file if you wish:

for dir in "$HOME/dir" /usr/src /usr/local/lib; do
    pushd -n "$dir" >/dev/null
end

or, if you want to put the directories in an array and use them from there instead:

dirstack=( "$HOME/dir"
           /usr/src
           /usr/local/lib )

for dir in "${dirstack[@]}"; do
    pushd -n "$dir" >/dev/null
end

unset dirstack

With -n, pushd won't actually change the working directory, but instead just add the given directory to the stack.

If you wish, you can store the value of the DIRSTACK array (upper-case variable name here), which is the current directory stack, into a file from ~/.bash_logout, and then read that file in ~/.bashrc rather than using a predefined array.

In ~/.bash_logout:

declare -p DIRSTACK >"$HOME/.dirstack"

In ~/.bashrc:

if [ -f "$HOME/.dirstack" ]; then
    source "$HOME/.dirstack"
fi

I don't know how well this would work in a situation where you use multiple terminals. The .dirstack file would be overwritten every time a terminal exited, if it ran a bash as a login shell.