--- title: "Installation" description: "Install, upgrade, inventory and remove the CAT PowerShell module" url: "https://docs.justcat.it/reference/powershell-module/installation/" --- # Installation The module is installed with `Install-Module`, upgraded with `Update-Module` and removed with `Uninstall-Module`. No administrator permissions are needed when installing into `CurrentUser` scope. ## Prerequisites ### PowerShell 7 The module declares `PowerShellVersion = '7.4'` and `CompatiblePSEditions = 'Core'`. Windows PowerShell 5 is not supported: `Install-Module CAT` completes there without an error, but the module does not work. | Version of CAT | Required version of PowerShell | |---|---| | `0.*` | 7.2 | | `1.*` | 7.4 | | `2.*` | 7.4 | PowerShell 7 releases with long-term support come out every second year and are supported for three years, so a PowerShell upgrade is needed at least once in three years. To find out which version is running, read the `PSVersion` row of: ```powershell $PSVersionTable ``` Microsoft's installation instructions for PowerShell 7 are at . If PowerShell 7 cannot be installed, use [CAT CLI](https://docs.justcat.it/reference/cat-cli/introduction/ "CAT CLI") instead — it is self-contained and has no dependency on PowerShell. ### Operating system Windows 10 or later and Windows Server 2016 or later, on both clients and servers. The module also runs on the Linux distributions where Microsoft supports PowerShell 7 — see [CAT on Linux](https://docs.justcat.it/how-to-guides/licensing-and-admin/cat-on-linux/ "CAT on Linux"). ### Provider drivers Some data source providers need additional software installed on the machine. The requirement belongs to the provider, not to the module — each provider page states what it needs, and the [Providers overview](https://docs.justcat.it/reference/data-sources/providers/overview/ "Providers overview") marks which providers need a driver. ## Install ```powershell Install-Module CAT -AcceptLicense -AllowClobber ``` `-Scope` decides who gets the module. `AllUsers` requires administrator permissions, `CurrentUser` does not: ```powershell Install-Module CAT -Scope AllUsers -AcceptLicense -AllowClobber # or Install-Module CAT -Scope CurrentUser -AcceptLicense -AllowClobber ``` `-RequiredVersion` installs one specific version; `-MinimumVersion` and `-MaximumVersion` bound the range: ```powershell $CatVersion = '3.0.0' Install-Module CAT -RequiredVersion $CatVersion -AcceptLicense -AllowClobber ``` Several versions of the module can be installed side by side — for example the version used in production and the latest one. `-Force` installs another version next to an existing one and suppresses the confirmation prompt that appears while the PowerShell Gallery is not a trusted repository (it is not, by default): ```powershell Install-Module CAT -Force -AcceptLicense -AllowClobber ``` > **🙀:** **In automated processes, always pin the version.** ```powershell Install-Module CAT -RequiredVersion '3.0.0' Import-Module CAT -RequiredVersion '3.0.0' ``` Breaking changes may appear between major versions. Pinning both the install and the import keeps a pipeline on the version the tests were developed against. ## List what is installed ```powershell Get-Module CAT -ListAvailable ``` The command lists every installed version of the module. To load one of them into the session, name it: ```powershell Import-Module CAT -RequiredVersion '3.0.0' ``` Without `-RequiredVersion`, `Import-Module CAT` loads the highest installed version. Importing is always required — see [Install and import](https://docs.justcat.it/reference/powershell-module/introduction/#install-and-import "Install and import") on the Introduction page. ## Upgrade ```powershell Update-Module -Name CAT ``` ## Uninstall One version: ```powershell Uninstall-Module CAT -RequiredVersion '2.4.0' ``` All installed versions: ```powershell Get-Module CAT -ListAvailable | Uninstall-Module -Force ``` Uninstalling removes the module only. Project files, test definitions and results stay where they are.