Cod is a completion daemon for {bash,fish,zsh}.

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


Download or build cod binary for your OS and put it into your $PATH.

Then you need to edit your init script and add few lines.


Add to ~/.bashrc

source <(cod init $$ bash)


Add to ~/.zshrc

source <(cod init $$ zsh)


Add to ~/.config/fish/

cod init %self fish | source

Supported shells and operating systems

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

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.

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


Go v1.16 is recommended.

git clone
cd cod
go build


go get -u


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:

  • checks if --help flag is used;
  • checks that command is simple i.e. doesn’t contain any pipes, file descriptor redirections, and other shell magic;
  • 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 program. (So it finds binary in PATH or resolves relative path if required). Other arguments except binary path are left unchanged.

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

If program is successfully executed cod will store:

  • absolute path to binary;
  • used arguments;
  • 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 of help pages and recognizes flags (starting with -) but doesn’t recognize subcommands.

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


Cod will search config in $XDG_CONFIG_HOME/cod/config.toml file (default: ~/.config/cod/config.toml).

Config file allows to specify rules to ignore executables or always trust them.

cod example-config prints example configuration to stdout. cod example-config --create writes example configuration to proper config file.

Data directories

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