Install-PowerShell

A cross‑platform GitHub Action that installs a specific PowerShell Core version—or the latest stable release—on any GitHub‑hosted runner (Linux, macOS, or Windows). The action automatically skips installation when the requested version is already present.

Usage

Add the action to a job in your workflow file:

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install PowerShell
        uses: PSModule/install-powershell@v1
        with:
          Version: 7.5.0

      - name: Run a PowerShell script
        shell: pwsh
        run: |
          Write-Host "Using PowerShell $($PSVersionTable.PSVersion)"

Inputs

Input	Required	Default	Description
Version	false	latest	Desired PowerShell Core version (e.g. 7.4.1). Use latest to install the newest stable release.

Secrets

This action does not require any secrets.

Outputs

This action does not generate any outputs.

How it works

• Version resolution If Version is set to latest (case‑insensitive), the action queries the GitHub API for the newest stable release tag in the PowerShell/PowerShell repository and substitutes that version.

• Skip logic Before installing, the action checks the current runner to see whether the requested version is already available (pwsh -Command $($PSVersionTable.PSVersion)). If it matches, the step ends immediately.

• Platform‑specific installers

  Runner OS	Install strategy
  Linux (Debian/Ubuntu‑based)	Uses APT if available; otherwise downloads the .deb asset directly from the release page and installs with dpkg.
  macOS	Prefers Homebrew Cask (brew install --cask powershell) and falls back to downloading the .pkg installer. ARCH detection (arm64 / x64) is automatic.
  Windows	Downloads the corresponding .msi package and installs silently with msiexec.

• Error handling The step fails with a clear error message if the requested version cannot be resolved or if the operating‑system distribution is unsupported (e.g., non‑APT Linux distros).