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about_Tab_Expansion

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Short description

PowerShell provides completions on input to provide hints, enable discovery, and speed up input entry. Command names, parameter names, argument values and file paths can all be completed by pressing the Tab key.

Long description

Tab expansion is controlled by the internal function TabExpansion or TabExpansion2. Since this function can be modified or overridden, this discussion is a guide to the behavior of the default PowerShell configuration.

Tab expansion behavior can also be modified by the Predictive IntelliSense feature of the PSReadLine module. For more information, see Predictive IntelliSense.

The Tab key is the default key binding on Windows. You can change the keybinding using the PSReadLine module or the application that's hosting PowerShell. For more information, see about_PSReadLine.

Note

One limitation of the tab expansion process is that tabs are always interpreted as attempts to complete a word. If you copy and paste command examples into a PowerShell console, make sure that the sample doesn't contain tabs. If it does, the results will be unpredictable and will almost certainly not be what you intended.

File and cmdlet name completion

To fill in a filename or path from the available choices automatically, type part of the name and press the Tab key. PowerShell automatically expands the name to the first match that it finds. Pressing the Tab key repeatedly cycles through all the available choices.

The tab expansion of cmdlet names is slightly different. To use tab expansion on a cmdlet name, type the entire first part of the name (the verb) and the hyphen that follows it. You can fill in more of the name for a partial match. For example, if you type get-co and then press the Tab key, PowerShell automatically expands this to the Get-Command cmdlet. Notice that it also changes the case of letters to their standard form. If you press Tab key again, PowerShell replaces this with the only other matching cmdlet name, Get-Content.

Tab completion also works to resolve PowerShell alias and native executables.

You can use tab expansion repeatedly on the same line. For example, you can use tab expansion on the name of the Get-Content cmdlet by entering:

Examples

PS> Get-Con<Tab>

When you press the Tab key, the command expands to:

PS> Get-Content

You can then partially specify the path to the Active Setup log file and use tab expansion again:

PS> Get-Content c:\windows\acts<Tab>

When you press the Tab key, the command expands to:

PS> Get-Content C:\windows\actsetup.log

PSReadLine also has a menu completion feature. The default key binding on Windows is Ctrl+Space.

PS> fore<Ctrl-Space>

When you press Ctrl+Space, PowerShell presents the full list of matching values as a menu:

PS> foreach
foreach         ForEach-Object  foreach.cmd

In this example the string 'fore' is matched to foreach (PowerShell alias), ForEach-Object (cmdlet), and foreach.cmd (native command). Use the arrow keys to select the value you want.

Parameter argument completion

Tab completion can also work to complete parameter arguments. You can use the Tab key to cycle through a list of possible values that are valid for some parameter. For more information, see about_Functions_Argument_Completion.

See also