I'm forever needing to search through files for various strings and either pipe them to the command line or send them to a file. Here's a couple commands to help out. From http://stackoverflow.com/questions/8153750/how-to-search-a-string-in-multiple-files-and-return-the-names-of-files-in-powers

SearchString.ps1

#push direct to the command line.
Get-ChildItem -recurse | Select-String -pattern "dummy" | group path | select name

# a little more setup, but pushes out to a txt file
# Nice for searching for specific errors in a bunch of log files.
$logdir = "SOMEDIR"
$csvpath = "SOMEPATH"
gci $logdir -rec *.txt | gc | select-string $pattern | add-content $csvpath