Installation
Otter runs on Windows, Linux and macOS. On Windows it needs Windows PowerShell 5.1 and nothing else; on Linux and macOS it needs PowerShell 7. There are no administrator rights, services, or system changes.
Release status: Stable release 1.0.0. Download: Available - get the zip from the Download page. You can also run Otter straight from a copy of the repository (below).
System requirements
Windows: Windows 10 or Windows 11 (64-bit) with Windows PowerShell 5.1 (powershell.exe, built into Windows). The otter.cmd launcher finds it for you, so you can start Otter from Command Prompt, Windows Terminal, or PowerShell 7 alike. Linux and macOS: PowerShell 7 (pwsh). A standard user account is enough everywhere, and a web browser is only needed for web applications.
Run from the project folder
Get the Otter project folder from GitHub, open Windows PowerShell in it, and run a program with otter.cmd:
PowerShell
git clone https://github.com/Heavens-Lava/otterPS.git
cd otterPS
.\otter.cmd --version
.\otter.cmd examples\hello.ot
No registry changes, environment variables, or background services are created. Add the folder to your PATH if you would like to type otter instead of .\otter.cmd.
Install from a release archive
When a versioned archive is published, extract it, open Windows PowerShell in the extracted folder, and run the per-user installer. It copies Otter to %LOCALAPPDATA%\Otter, adds it to your user PATH, and runs a health check:
PowerShell
Set-ExecutionPolicy -Scope Process Bypass
.\Install-Otter.ps1 -AddToUserPath
Open a new terminal so the updated PATH takes effect, then verify:
PowerShell
otter --version
Output
Otter 1.0.0
Linux and macOS
Otter runs on Linux and macOS with PowerShell 7 (pwsh). The release archive is the same one Windows uses: next to otter.cmd it carries an otter command for Linux and macOS. Install PowerShell 7 from https://aka.ms/install-powershell, extract the archive, open a terminal in the extracted folder, and run the installer with pwsh:
Shell
pwsh -NoProfile -File ./Install-Otter.ps1 -AddToUserPath
otter --version
The installer copies Otter to ~/.local/share/otter/1.0.0 and writes an otter command to ~/.local/bin. If that folder is not on your PATH yet, it prints the export line to add to ~/.zshrc or ~/.bashrc; open a new terminal afterwards. To run Otter without installing it, use ./otter in the extracted folder or the project folder, for example ./otter run hello.ot.
Console programs, files, JSON, dates, HTTP, running commands, modules, projects, tests and web applications work on Linux and macOS. Desktop windows (otter desktop), the registry, the event log, stored credentials, printing, notifications, file dialogs, file owners and power actions need Windows: on Linux and macOS they stop with a clear "only available on Windows" message. Build a desktop program as a web application instead with otter web. The clipboard needs a clipboard program (pbcopy on macOS; xclip, xsel or wl-copy on Linux).
Verify your installation
PowerShell
otter # starts the interactive REPL (type exit to leave)
otter check hello.ot # validates a program without running it
Troubleshooting
"Running scripts is disabled on this system": allow scripts for the current terminal only with Set-ExecutionPolicy -Scope Process Bypass. It expires when you close the window.
"otter is not recognized": open a fresh terminal so the new PATH is picked up, and confirm the install folder is in your user PATH.
Uninstall
PowerShell
Set-ExecutionPolicy -Scope Process Bypass
& "$env:LOCALAPPDATA\Otter\1.0.0\Uninstall-Otter.ps1"
On Linux and macOS: pwsh -NoProfile -File ~/.local/share/otter/1.0.0/Uninstall-Otter.ps1. It also removes the otter command from ~/.local/bin.
Next: write your first program