nepo is a cli tool that open files with a program depending on the file extension.

For example, nepo image.png could open it with the viu terminal image viewer and nepo book.epub with the epy epub reader.

• nepo is configured at ~/.nepo.yml with simple association rules

  epubs:
    ext: 
      - epub
      - epub3
    cmd: epy ${file}
  

• nepo --mode=foo file.ext allow you to select a different program to open the file

• nepo is best used with shell aliases such as function view() { nepo --mode=view "$@" }

• Can iterate over multiple files or open them all at once.

• Have a look at my personal configuration file

With cargo:

$ cargo install nepo

You must create a nepo configuration file in your home directory named ~/.nepo.yml.

default:
  cmd: vim -p ${files}

markdown:
  ext: md
  cmd: glow ${file}
  
images:
  ext: 
    - png
    - jpg
  cmd: viu ${files}

This yaml file contains associations that match file extensions to commands. If the file doesn't match any assocation, the top one will be used.

The cmd configuration accepts ${file} and ${files} as parameters. The singular variant contains the first filename provided, while the plural will contains them all.

If multiple files are provided, only the files with the matching extensions will be provided to the command.

If multiple associations match a file the last one gets priority.

If you call nepo with a mode (nepo --mode=view), It will only consider assocations with the selected mode.

view_json:
  mode: view
  ext: json
  cmd: jless ${file}

You can define any mode you want, but the edit and view mode can be used with the shorthands nepo --view, -v, --edit, -e