> ## Documentation Index
> Fetch the complete documentation index at: https://tally.wharflab.com/llms.txt
> Use this file to discover all available pages before exploring further.

# powershell/PSUseCompatibleCommands

> Use compatible commands

`powershell/PSUseCompatibleCommands` is a PSScriptAnalyzer diagnostic emitted by tally for PowerShell snippets embedded in Dockerfiles.

| Property | Value            |
| -------- | ---------------- |
| Severity | Warning          |
| Category | PSScriptAnalyzer |
| Auto-fix | No               |

## Description

This rule identifies commands that are not available on a targeted PowerShell platform.

<Note>
  This page describes upstream PSScriptAnalyzer compatibility profiles. tally runs the analyzer through PowerShell 7 (`pwsh`); Windows PowerShell 5.1
  (`powershell.exe`) is out of scope as a sidecar host.
</Note>

A PowerShell platform is identified by a name in the following format:

```text theme={null}
`<os-name>`_`<os-arch>`_`<os-version>`_`<ps-version>`_`<ps-arch>`_`<dotnet-version>`_`<dotnet-edition>`
```

Where:

* `<os-name>`: The name of the operating system PowerShell is running on.
  On Windows, this includes the SKU number.
  On Linux, this is the name of the distribution.
* `<os-arch>`: The machine architecture the operating system is running on (this is usually `x64`).
* `<os-version>`: The self-reported version of the operating system (on Linux, this is the
  distribution version).
* `<ps-version>`: The PowerShell version (from `$PSVersionTable.PSVersion`).
* `<ps-arch>`: The machine architecture of the PowerShell process.
* `<dotnet-version>`: The reported version of the .NET runtime PowerShell is running on (from
  `System.Environment.Version`).
* `<dotnet-edition>`: The .NET runtime flavor PowerShell is running on (currently `framework` or
  `core`).

For example:

* `win-4_x64_10.0.18312.0_5.1.18312.1000_x64_4.0.30319.42000_framework` is PowerShell 5.1 running on
  Windows 10 Enterprise (build 18312) for x64.
* `win-4_x64_10.0.18312.0_6.1.2_x64_4.0.30319.42000_core` is PowerShell 6.1.2 running on the same
  operating system.
* `ubuntu_x64_18.04_6.2.0_x64_4.0.30319.42000_core` is PowerShell 6.2.0 running on Ubuntu 18.04.

Some platforms come bundled with PSScriptAnalyzer as JSON files, named in this way for targeting in
your configuration.

Platforms bundled by default are:

| PowerShell Version | Operating System       | ID                                                                    |
| :----------------: | ---------------------- | --------------------------------------------------------------------- |
|         3.0        | Windows Server 2012    | `win-8_x64_6.2.9200.0_3.0_x64_4.0.30319.42000_framework`              |
|         4.0        | Windows Server 2012 R2 | `win-8_x64_6.3.9600.0_4.0_x64_4.0.30319.42000_framework`              |
|         5.1        | Windows Server 2016    | `win-8_x64_10.0.14393.0_5.1.14393.2791_x64_4.0.30319.42000_framework` |
|         5.1        | Windows Server 2019    | `win-8_x64_10.0.17763.0_5.1.17763.316_x64_4.0.30319.42000_framework`  |
|         5.1        | Windows 10 Pro         | `win-48_x64_10.0.17763.0_5.1.17763.316_x64_4.0.30319.42000_framework` |
|         6.2        | Ubuntu 18.04 LTS       | `ubuntu_x64_18.04_6.2.4_x64_4.0.30319.42000_core`                     |
|         6.2        | Windows 10.0.14393     | `win-8_x64_10.0.14393.0_6.2.4_x64_4.0.30319.42000_core`               |
|         6.2        | Windows 10.0.17763     | `win-8_x64_10.0.17763.0_6.2.4_x64_4.0.30319.42000_core`               |
|         6.2        | Windows 10.0.18362     | `win-4_x64_10.0.18362.0_6.2.4_x64_4.0.30319.42000_core`               |
|         7.0        | Ubuntu 18.04 LTS       | `ubuntu_x64_18.04_7.0.0_x64_3.1.2_core`                               |
|         7.0        | Windows 10.0.14393     | `win-8_x64_10.0.14393.0_7.0.0_x64_3.1.2_core`                         |
|         7.0        | Windows 10.0.17763     | `win-8_x64_10.0.17763.0_7.0.0_x64_3.1.2_core`                         |
|         7.0        | Windows 10.0.18362     | `win-4_x64_10.0.18362.0_7.0.0_x64_3.1.2_core`                         |

Other profiles can be found in the [GitHub repo][02].

You can also generate your own platform profile using the [PSCompatibilityCollector module][01].

The compatibility profile settings takes a list of platforms to target under `TargetProfiles`. A
platform can be specified as:

* A platform name (like `ubuntu_x64_18.04_6.1.1_x64_4.0.30319.42000_core`), which will have `.json`
  added to the end and is searched for in the default profile directory.
* A filename (like `my_custom_platform.json`), which will be searched for in the default profile
  directory.
* An absolute path to a file (like `D:\PowerShellProfiles\TargetMachine.json`).

The default profile directory is under the PSScriptAnalyzer module at
`$PSScriptRoot/compatibility_profiles` (where `$PSScriptRoot` here refers to the directory
containing `PSScriptAnalyzer.psd1`).

The compatibility analysis compares a command used to both a target profile and a 'union' profile
(containing all commands available in *any* profile in the profile dir). If a command is not present
in the union profile, it is assumed to be locally created and ignored. Otherwise, if a command is
present in the union profile but not present in a target, it is deemed to be incompatible with that
target.

## Configuration settings

| Configuration key | Meaning                                                                          | Accepted values                                                                          | Mandatory                                                                      | Example                                                                                                                       |
| ----------------- | -------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------- |
| `Enable`          | Activates the rule                                                               | bool (`$true`/`$false`)                                                                  | No (default: `$false`)                                                         | `$true`                                                                                                                       |
| `TargetProfiles`  | The list of PowerShell profiles to target                                        | string\[]: absolute paths to profile files or names of profiles in the profile directory | No (default: `@()`)                                                            | `@('ubuntu_x64_18.04_6.1.3_x64_4.0.30319.42000_core', 'win-48_x64_10.0.17763.0_5.1.17763.316_x64_4.0.30319.42000_framework')` |
| `ProfileDirPath`  | The location to search for profiles by name and use for union profile generation | string: absolute path to new profile dir                                                 | No (defaults to `compatibility_profiles` directory in PSScriptAnalyzer module) | `C:\Users\me\Documents\pssaCompatProfiles`                                                                                    |
| `IgnoreCommands`  | Commands to ignore compatibility of in scripts                                   | string\[]: names of commands to ignore                                                   | No (default: `@()`)                                                            | `@('Get-ChildItem','Import-Module')`                                                                                          |

An example configuration might look like:

```powershell theme={null}
@{
    Rules = @{
        PSUseCompatibleCommands = @{
            Enable = $true
            TargetProfiles = @(
                'ubuntu_x64_18.04_6.1.3_x64_4.0.30319.42000_core'
                'win-48_x64_10.0.17763.0_5.1.17763.316_x64_4.0.30319.42000_framework'
                'MyProfile'
                'another_custom_profile_in_the_profiles_directory.json'
                'D:\My Profiles\profile1.json'
            )
            # You can specify commands to not check like this, which also will ignore its parameters:
            IgnoreCommands = @(
                'Install-Module'
            )
        }
    }
}
```

## Suppression

Command compatibility diagnostics can be suppressed with an attribute on the `param` block of a
scriptblock as with other rules.

```powershell theme={null}
[System.Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseCompatibleCommands', '')]
```

The rule can also be suppressed only for particular commands:

```powershell theme={null}
[System.Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseCompatibleCommands',
    'Start-Service')]
```

And also suppressed only for parameters:

```powershell theme={null}
[System.Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseCompatibleCommands',
    'Import-Module/FullyQualifiedName')]
```

[01]: https://github.com/PowerShell/PSScriptAnalyzer/tree/main/PSCompatibilityCollector

[02]: https://github.com/PowerShell/PSScriptAnalyzer/tree/main/PSCompatibilityCollector/optional_profiles

## Source

This rule documentation is adapted from Microsoft's PSScriptAnalyzer documentation for
[UseCompatibleCommands](https://github.com/MicrosoftDocs/PowerShell-Docs-Modules/blob/main/reference/docs-conceptual/PSScriptAnalyzer/Rules/UseCompatibleCommands.md),
licensed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).