Installation

Lask is a single binary; it needs Docker to run containers. Pick your platform below, then take the Getting started guide.

macOS · Homebrew

$ brew tap lask-task-runner/tap
$ brew trust lask-task-runner/tap
$ brew install lask

macOS / Linux · download the binary

$ VERSION=$(curl -fsSL https://api.github.com/repos/lask-task-runner/lask/releases/latest | grep -m1 '"tag_name"' | cut -d '"' -f4)
$ TARGET=linux-amd64 # or macos-amd64, macos-arm64
$ curl -fsSL -o lask.tar.gz "https://github.com/lask-task-runner/lask/releases/download/${VERSION}/lask-${VERSION}-${TARGET}.tar.gz"
$ tar -xzf lask.tar.gz
$ sudo mv ./lask /usr/local/bin

Uninstall with sudo rm /usr/local/bin/lask.

Debian / Ubuntu · .deb package

$ VERSION=$(curl -fsSL https://api.github.com/repos/lask-task-runner/lask/releases/latest | grep -m1 '"tag_name"' | cut -d '"' -f4)
$ curl -fsSL -o lask.deb "https://github.com/lask-task-runner/lask/releases/download/${VERSION}/lask-${VERSION}-linux-amd64.deb"
$ sudo dpkg -i lask.deb

amd64 only; on another architecture, take the tarball above. Uninstall with sudo apt remove lask.

Windows · PowerShell

> $version = (Invoke-RestMethod https://api.github.com/repos/lask-task-runner/lask/releases/latest).tag_name
> Invoke-WebRequest -Uri "https://github.com/lask-task-runner/lask/releases/download/$version/lask-$version-windows-amd64.zip" -OutFile lask.zip
> Expand-Archive -Path lask.zip -DestinationPath "$env:LOCALAPPDATA\Programs\lask" -Force
> setx PATH "$env:PATH;$env:LOCALAPPDATA\Programs\lask"

Restart your terminal for the updated PATH to take effect. Uninstall with Remove-Item -Recurse -Force "$env:LOCALAPPDATA\Programs\lask".

From source · Haskell toolchain

Needs GHCup or brew install haskell-stack.

$ stack --local-bin-path /usr/local/bin/ install

Verify with lask version. Lask runs containers through the docker command, so Docker must be installed and its daemon running (Docker Desktop on macOS and Windows, Docker Engine on Linux). Archives and packages for every platform are on the latest release; an APT repository and Chocolatey support are planned.

Shell completion · bash, zsh, fish

Completion knows your module, not just the CLI: it completes the functions the repository you are standing in defines, each function's keyword parameters, and the commands it declares.

$ lask run <TAB>
build-on-docker     install             test                uninstall-completion
doctest             install-completion  uninstall           unittest
$ lask run install --<TAB>
--output  --env  --help
$ lask run install --env <TAB>
docker  local
$ lask cmd <TAB>
mv  rm  stack  uname

fish — nothing else to do:

$ lask completion fish > ~/.config/fish/completions/lask.fish

bash — write the script somewhere and source it:

$ mkdir -p ~/.bash_completion.d
$ lask completion bash > ~/.bash_completion.d/lask

then, in ~/.bash_profile (macOS Terminal starts a login shell, which does not read ~/.bashrc) or in ~/.bashrc (Linux):

source ~/.bash_completion.d/lask

With the bash-completion package installed — most Linux distributions have it — writing the script to ~/.local/share/bash-completion/completions/lask instead loads it on demand, with nothing added to your rc file. That directory does nothing on a system without the package, which includes a stock macOS. Note that source <(lask completion bash) cannot be used there either: the source builtin in bash 3.2, still macOS's /bin/bash, silently reads nothing from a process substitution.

zsh — the completion system has to be switched on, which macOS does not do for you:

$ mkdir -p ~/.zsh/completions
$ lask completion zsh > ~/.zsh/completions/_lask

then, in ~/.zshrc:

fpath=(~/.zsh/completions $fpath)
autoload -Uz compinit && compinit

If compinit already runs in your ~/.zshrc — every framework does it for you — only the fpath line is new, and any directory already on $fpath works just as well. compinit caches what it found, so after adding a file, delete ~/.zcompdump* and open a new shell. If completion does nothing and command not found: compdef appears when zsh starts, compinit has not run.

The script only ever asks the binary, so it keeps working across upgrades. Completion reads your module without running it: no task, no default value, and no environment is ever evaluated to answer a <TAB>.

Editor support

lask serve is a language server built into the same binary. Install the Lask extension from the VS Code Marketplace, or search for "Lask" in VS Code.