Finding Text in Files (grep)

Command Equivalents

Description

Select-String is the powerful PowerShell equivalent of grep. It is designed to search for text patterns inside strings and files.

A key difference from grep is that Select-String doesn’t just return the matching text line; it returns a MatchInfo object. This object contains rich information about each match found, including the filename, the line number, and the line’s content, making the results easy to use programmatically.

By default, searches are case-insensitive.

Common PowerShell Pattern: Find then Grep

For recursive searching (the equivalent of grep -r), the most common and powerful pattern in PowerShell is to first find the files you want to search using Get-ChildItem and then pipe the results to Select-String.

# General Pattern
Get-ChildItem <path-and-filters> | Select-String -Pattern "my-text"

This approach is highly flexible, allowing you to use all the power of Get-ChildItem’s filtering capabilities to select a precise set of files before searching within them.

Common Usage

Searching in a Single File

To search for a simple text pattern in one file, use the -Pattern and -Path parameters.

# Find all lines containing "Error" in the application log
Select-String -Path ".\application.log" -Pattern "Error"

Searching Recursively (The grep -r Equivalent)

This example finds all .xml files in the current directory and its subdirectories, then searches inside them for the text “connectionString”.

# Find all XML files, then search within them
Get-ChildItem -Recurse -Filter "*.xml" | Select-String -Pattern "connectionString"

Case-Sensitive Search

To perform a case-sensitive search, add the -CaseSensitive switch.

# Find the exact text "ADMIN", not "admin" or "Admin"
Select-String -Path ".\permissions.log" -Pattern "ADMIN" -CaseSensitive

Inverting the Match (grep -v)

To find lines that do not contain a pattern, use the -NotMatch parameter.

# Find all lines that do not contain the word "deprecated"
Get-Content ".\config.ini" | Select-String -Pattern "deprecated" -NotMatch