The command line

PowerShell 7 comes with a module called PSReadLine. A module is a collection of related commands. Modules are explored in greater detail in Chapter 2, Modules.

PSReadLine provides command-line syntax highlighting, preserves history between sessions, and offers completion services when writing commands.

PSReadLine can be configured to offer command completion based on previously typed commands, a useful feature when using similar commands in the console and one that can save searching history for the right command. By default, PSReadline 2.2.6 uses history and a command prediction plugin. The plugin may be explicitly enabled using Set-PSReadLineOption.

Set-PSReadLineOption -PredictionSource HistoryAndPlugin

Once enabled, PSReadLine will offer suggestions based on typed content that may be completed using Tab as shown in Figure 1.1.

Figure 1.1: PSReadLine Predictive completion

By default, Tab can be used to complete any command or parameter, and a variety of arguments for parameters. In addition to Tab completion, PSReadLine allows the use of Control and Space to provide menu style completion. For example, entering the following partial command:

Get-ChildItem -

Then pressing Control and Space (immediately after the hyphen) will show a menu that can be navigated using the cursor keys, as shown in Figure 1.2:

Figure 1.2: PSReadLine List completion

In PowerShell, the prompt displayed is controlled by a function named prompt. A very simple prompt can be set as shown below:

function prompt {
    "$env:USERNAME $pwd PS>"
}

The default prompt can be restored by restarting PowerShell. A profile script is required to make changes on console restart. See about_profiles for more information:

Get-Help about_profiles

Several modules and tools exist to help customize prompts in PowerShell:

• PowerLine: https://github.com/Jaykul/PowerLine
• oh-my-posh: https://ohmyposh.dev/
• Starship: https://starship.rs/

PowerShell is a complex language; a good editor can save time finding the right syntax to use in a script.