To open a file relative to the current one in Helix, you can to the do the following with 24.3:
:o <C-r>%<C-w>
Here, the Control-R allows you to select a register and the special register “%” contains the current file path and inserts into the command line, while the final Control-w chops off the last part of the file name leaving with you current directory.
This is like :o %:h
from Vim/Neovim
Here’s a better method for Helix: Bind a key to open a file picker relative to the current buffer. This useful command does not seem to be bound to a key by default. Choosing “<space>%” may be memorable because % is a reminder of the current file. Add this to ~/.config/helix/config.toml: