Cod is a completion daemon for bash, fish, and zsh.

It detects usage of --help commands, parses their output, and generates auto-completions for your shell.

Install

You can either download or build the cod binary for your OS and put it into your $PATH.

After that, you will need to edit your init script (e.g. ~/.config/fish/config.fish, ~/.zshrc, ~/.bashrc) and add a few lines for the daemon to work correctly.

Bash

Add the following to your ~/.bashrc

   source <(cod init $$ bash)

Zsh

Make sure completion system is initialized.

Add the following to your ~/.zshrc

   source <(cod init $$ zsh)

Or, you can use a plugin manager like zinit:

   zinit wait lucid for \
     dim-an/cod

Initializing zsh completion system

cod requires initialized completion system. In many cases it is already the case (e.g. if you are using oh-my-zsh or similar framework).

You can check whether your completion system is already initilized by using type compdef command:

  # Completion system IS initialized
  $ type compdef
  compdef is a shell function from /usr/share/zsh/functions/Completion/compinit

  # Completion system IS NOT initialized
  $ type compdef
  compdef not found

If you found that you need to initialize completion system you can do this by:

• calling compinit function in your .zshrc before initializing cod itself, or

• executing compinstall command from your shell, it will modify .zshrc file for you.

  Also check zsh documentation.

Fish

Add the following to ~/.config/fish/config.fish

   cod init $fish_pid fish | source

Fig

As an alternative, you can also install cod with Fig in bash, zsh, or fish with just one click.

Supported shells and operating systems

• zsh cod is known to work with latest version of zsh (tested: v5.5.1 and 5.7.1) on macOS and Linux.

• bash cod also works with with latest version of bash (tested: 4.4.20 and v5.0.11) on Linux.

  Note that default bash that is bundled with macOS is too old and cod doesn't support it.

• fish cod works with latest version of fish (tested: v3.1.2) on Linux (I didn't have a chance to test it on macOS).

Building cod

It is recommended that you have at least Go v1.19 installed on your machine

  git clone https://github.com/dim-an/cod.git
  cd cod
  go build

or

  go get -u github.com/dim-an/cod

Overview

Cod checks each command you run in the shell. When cod detects usage of --help flag it asks if you want it to learn this command. If you choose to allow cod to learn this command cod will run command itself parse the output and generate completions based on the --help output.

How cod detects help commands

Cod performs following checks to decide if command is help invocation:

1. checks if the --help flag is used
2. checks that command is simple i.e. doesn't contain any pipes, file descriptor redirections, and other shell magic

3. checks that command exit code is 0.

   If cod cannot automatically detect that your command is help invocation you can use learn subcommand to learn this command anyway.

How cod runs help commands

Cod always uses absolute paths to run programs. (So it finds the binary in $PATH or resolves relative path if required). Arguments other than the binary path are left unchanged.

The current shell environment and current working directory will be used.

If the program is successfully executed, cod will store:

• the absolute path to binary
• any used arguments
• the working directory
• environment variables This info will be used to update command if required (check: cod help update).

How cod parses help output

cod has generic parser that works with most help pages and recognizes flags (starting with -), while not recognizing subcommands.

It also has a special parser tuned for the python argparse library that recognizes flags and subcommands.

Configuration

Cod will search for the default config file $XDG_CONFIG_HOME/cod/config.toml.

The config file allows you to specify rules to either ignore or trust specified binaries

cod example-config prints an example configuration to stdout.

cod example-config --create writes an example config to the default directory of said config file ($XDG_CONFIG_HOME/cod/config.toml)

Data directories

cod uses $XDG_DATA_HOME/cod (default: ~/.local/share/cod) to store all generated data files.