Move duplicated folder name up one level

I have a folder structure:

/mnt/data/mydata/mydata/several-files-and-folders-here

I would like it to instead be:

/mnt/data/mydata/several-files-and-folders-here

I tried mv but it complains the folder isn't empty, and I wasn't able to find a feasible fast solution that I understood, I'm still new to learning Linux. How would one fix this correctly?

How it's done

The way it's done is you'd need to move the contents of:

/mnt/data/mydata/mydata/

to

/mnt/data/mydata/

first ... And afterwords you can just delete the now empty directory, if you like, with e.g.:

rmdir -v /mnt/data/mydata/mydata/

rmdir is safe ... It will only delete the directory if it's empty and error otherwise.

How to move

Either (with no dry-run) simply:

echo mv -nv -- /mnt/data/mydata/mydata/* /mnt/data/mydata/

Notice: echo before mv is just a safe guard from accidental copy/paste ... You need to remove it for the command to work ... No dry-run here, so be careful.

Or (with a dry-run) utilizing bash's shell parameter expansion around either of the repeated directory names (e.g. either the leading one with: "${parameter/mydata\//}" or the trailing one with:"${parameter%mydata/*}${parameter##*/}") and a for loop ... A one-liner would be something as simple as:

for f in /mnt/data/mydata/mydata/*; do echo mv -nv -- "${f}" "${f%mydata/*}${f##*/}"; done

Notice: echo is inserted before mv for a safe dry-run ... Remove echo only when satisfied with the output and run the command again to do the actual moving.

Demonstration:

$ tree /mnt
/mnt
└── data
    └── mydata
        └── mydata
            ├── dir1
            │   ├── file1
            │   ├── file2
            │   └── file3
            ├── dir2
            │   ├── file1
            │   ├── file2
            │   └── file3
            ├── dir3
            ├── file1
            ├── file2
            └── file3

6 directories, 9 files
$ for f in /mnt/data/mydata/mydata/*; do mv -nv -- "${f}" "${f%mydata/*}${f##*/}"; done
renamed '/mnt/data/mydata/mydata/dir1' -> '/mnt/data/mydata/dir1'
renamed '/mnt/data/mydata/mydata/dir2' -> '/mnt/data/mydata/dir2'
renamed '/mnt/data/mydata/mydata/dir3' -> '/mnt/data/mydata/dir3'
renamed '/mnt/data/mydata/mydata/file1' -> '/mnt/data/mydata/file1'
renamed '/mnt/data/mydata/mydata/file2' -> '/mnt/data/mydata/file2'
renamed '/mnt/data/mydata/mydata/file3' -> '/mnt/data/mydata/file3'
$ tree /mnt
/mnt
└── data
    └── mydata
        ├── dir1
        │   ├── file1
        │   ├── file2
        │   └── file3
        ├── dir2
        │   ├── file1
        │   ├── file2
        │   └── file3
        ├── dir3
        ├── file1
        ├── file2
        ├── file3
        └── mydata

6 directories, 9 files