Merge two directory and does not overwrite things.

merge_dirs

#!/bin/bash

# To install in in: /usr/local/bin/merge_dirs
# Then: chmod +x /usr/local/bin/merge_dirs

set -eu

# Source: https://unix.stackexchange.com/a/155633
# Usage: like mv but: SRC DEST

DEST="${@:${#@}}"
ABS_DEST="$(cd "$(dirname "$DEST")"; pwd)/$(basename "$DEST")"

OVERRIDE=false

for SRC in "${@:1:$((${#@} -1))}"; do   (
    cd "$SRC";
    echo "cd $SRC"
    find . -type d -exec mkdir -p "${ABS_DEST}"/\{} \;
    # We do not override !
    find . -type f -exec mv -n \{} "${ABS_DEST}"/\{} \;
    find . -type d -empty -delete
) done

rmdir "$SRC"

if [[ -d "$SRC" ]]; then
  tree "$SRC"
  echo "Success: Directory $SRC had un-moved duplicates"
  echo "Run: diff -r -d '$SRC' '$DEST' | not grep -v '^Only in $DEST'"
  echo "If you are sure to delete source: rm -rf '$SRC'"
else
  echo "Success: Directory $SRC has been merged into $ABS_DEST"
fi