Using Tab Expansion

Command-line shells often provide a way to complete the names of long files or commands automatically, speeding up command entry and providing hints. Windows PowerShell allows you to fill in file names and cmdlet names by pressing the Tab key.


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 Windows PowerShell configuration.

To fill in a filename or path from the available choices automatically, type part of the name and press the Tab key. Windows PowerShell will automatically expand the name to the first match that it finds. Pressing the Tab key repeatedly will cycle through all of 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, Windows PowerShell will automatically expand 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, Windows PowerShell replaces this with the only other matching cmdlet name, Get-Content.

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:

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

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 Windows PowerShell console, make sure that the sample does not contain tabs; if it does, the results will be unpredictable and will almost certainly not be what you intended.