How to grep with PowerShell

Unix and Linux have had the incredibly powerful grep tool for decades but windows has always been lacking. PowerShell brings the functionality of grep with the Select-String cmdlet.

Use Select-String to Grep a Single File

To grep a simple text file is as easy as:
Select-String -Path "D:\script\Lorem-Ipsum.txt" -Pattern 'Tachytelic'

You can also use a wildcard:
Select-String -Path "D:\script\*.txt" -Pattern 'Tachytelic'

Grep Recursively with Get-Childitem

Unlike grep, Select-String does not have the ability to search recursively, but you can pipe output to it from Get-ChildItem, like this:
Get-ChildItem -Path "D:\Script\*.txt" -Recurse | Select-String -Pattern 'tachytelic'

Piping to Select-String

Just like grep, you can pipe to Select-String like this:
Get-Content "D:\Script\Lorem-Ipsum.txt" |Select-String "tachytelic"

If you want to make it more like Unix/Linux, add an alias to the Select-String cmdlet:
Set-Alias -Name grep -Value Select-String

Then you can simply pipe to Select-String like this:
cat "D:\Script\Lorem-Ipsum.txt" |grep "tachytelic"

Loop through results from Select-String

Here is an example that greps for a string and uses the results in a loop to determine if some action should be taken:

$pattern = "tachytelic"
$files = Select-String -Path "d:\script\*.txt" -Pattern $pattern
foreach ($file in $files) {
  $filename=$file.Filename
    $item = get-item $file.Path
    "File '{0}' matches the pattern '{1}'" -f $item.FullName, $pattern
    "It was last modified on {0}" -f $item.LastWriteTime
 
  $response = Read-Host -Prompt "Set the archive bit on this file?" 
  If ($response -eq 'Y') {
    $item.attributes="Archive"
    }
}

Which produces output like this:

grepping in Powershell seems to be incredibly fast, I have not conducted any testing against the performance of GNU Grep, but I don’t think you will be disappointed by the performance.