Make a New File in the Same Directory in Vim

TLDR
:w %:h/my-new-file.txt # write current buffer to a file in the same directory as the file you are editing
:sav %:h/my-new-file.txt # save current buffer to a file in the same directory as the file you are editing

Making a new file

To make a new file in vim type:

:w my-new-file.txt

: enters command mode
w writes
my-new-file.txt is the name of the file

The new file is written in the root directory where you opened vim. So given this project structure:

├── fileA.txt
└── somedir
    └── fileB.txt

Your new file will end up in in the root.

├── fileA.txt
├── my-new-file.txt
└── somedir
    └── fileB.txt

This might not be what you want. If you want the file to be created in another directory, you can specify it.

:w somedir/my-new-file.txt

├── fileA.txt
└── somedir
    ├── fileB.txt
    └── my-new-file.txt

This works well enough. But it gets harder if you have a deeply nested project structure. Given this structure:

├── fileA.txt
└── somedir
    └── otherdir
        └── more
            └── evenmore
                └── wow
                    └── fileB.txt

You would have to type

:w somedir/otherdir/more/evenmore/wow/my-new-file.txt

That's too long.

Making a new file in the same directory

To make a new file in the same directory as the file you are currently editing, and with the same contents, type:

:w %:h/my-new-file.txt

% refers to the current file
:h removes the last component and any separator, which means somedir/somename.txt becomes somedir and /my-new-file.txt is the literal value to append.

Why not use Nerd Tree?

I don't want to use Nerd Tree. I never need it, and I can't rely on it being installed on remote systems.

Why not use netrw?

I do. But for this it's faster to type the command above.

When do you use this?

Given this structure:

├── main.tom
└── services
    └── service1.tom

and a file I'm editing called service1.tom that looks like this:

class Service1 {
  do {
    // logic
  }
}

If I want to make a file called service2.tom that is mostly the same as service1.tom, I can do so by typing:

:w %:h/service2.tom

Thanks

Thanks to the folks at /r/vim who helped me understand what #:h was doing. https://www.reddit.com/r/vim/comments/k8lsfy/please_help_me_understand_h/