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about_Wildcards

  • Artikkeli

Short description

Describes how to use wildcard characters in PowerShell.

Long description

Wildcard characters represent one or many characters. You can use them to create word patterns in commands. Wildcard expressions are used with the -like operator or with any parameter that accepts wildcards.

For example, to match all the files in the C:\Techdocs directory with a .ppt file name extension, type:

Get-ChildItem C:\Techdocs\*.ppt

In this case, the asterisk (*) wildcard character represents any characters that appear before the .ppt file name extension.

Wildcard expressions are simpler than regular expressions. For more information, see about_Regular_Expressions.

PowerShell supports the following wildcard characters:

  • * - Match zero or more characters
    • a* matches aA, ag, and Apple
    • a* doesn't match banana
  • ? - For strings, match one character in that position
    • ?n matches an, in, and on
    • ?n doesn't match ran
  • ? - For files and directories, match zero or one character in that position
    • ?.txt matches a.txt and b.txt
    • ?.txt doesn't match ab.txt
  • [ ] - Match a range of characters
    • [a-l]ook matches book, cook, and look
    • [a-l]ook doesn't match took
  • [ ] - Match specific characters
    • [bc]ook matches book and cook
    • [bc]ook doesn't match hook
  • `* - Match any character as a literal (not a wildcard character)
    • 12`*4 matches 12*4
    • 12`*4 doesn't match 1234

You can include multiple wildcard characters in the same word pattern. For example, to find text files with names that begin with the letters a through l, type:

Get-ChildItem C:\Techdocs\[a-l]*.txt

Note

Wildcard matching for filesystem items works differently than for strings. For more information, see the Remarks section of the DirectoryInfo.GetFiles(String, EnumerationOptions) method.

There may be cases where you want to match the literal character rather than treat it as a wildcard character. In those cases you can use the backtick (`) character to escape the wildcard character so that it is compared using the literal character value. For example, '*hello`?*' matches strings containing "hello?".

Many cmdlets accept wildcard characters in parameter values. The Help topic for each cmdlet describes which parameters accept wildcard characters. For parameters that accept wildcard characters, their use is case-insensitive.

You can use wildcard characters in commands and script blocks, such as to create a word pattern that represents property values. For example, the following command gets services in which the ServiceType property value includes Interactive.

Get-Service | Where-Object {$_.ServiceType -Like "*Interactive*"}

In the following example, the If statement includes a condition that uses wildcard characters to find property values. If the restore point's Description includes PowerShell, the command adds the value of the restore point's CreationTime property to a log file.

$p = Get-ComputerRestorePoint
foreach ($point in $p) {
  if ($point.description -like "*PowerShell*") {
    Add-Content -Path C:\TechDocs\RestoreLog.txt "$($point.CreationTime)"
  }
}

See also