Search: grep & rg

Search Commands

grep and rg for pattern matching and recursive search.

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grep

Search for patterns in files or filter pipeline objects by matching against their text representation.

grep [OPTIONS] PATTERN [FILE...]

Two Modes

grep operates in two distinct modes depending on how you call it:

Pipeline mode

When objects are piped in and no file arguments are given, grep matches against each object’s BashText representation and emits the original typed object on match.

ls -la | grep '.ps1'

-rw-r--r-- 1 you you 141234 Apr  2 10:30 PsBash.psm1
-rw-r--r-- 1 you you  28400 Apr  2 10:28 PsBash.Tests.ps1

The output looks like text, but each result is still an LsEntry object:

$result = ls -la | grep '.ps1'
$result[0].GetType().Name   # PSCustomObject (LsEntry type)
$result[0].Name             # "PsBash.psm1"
$result[0].SizeBytes        # 141234
$result[0].Permissions      # "-rw-r--r--"

This is the pipeline bridge pattern: grep reads .BashText for matching but passes through the original object unchanged. Types survive the entire pipeline:

$big = ls -la | grep '.ps1' | sort -k5 -rn | head 1
$big[0].SizeBytes   # 141234 -- still a real integer

File mode

When file paths are given as arguments, grep reads the files and returns GrepMatch objects.

grep 'function' src/PsBash.psm1

function Get-BashPlatform {
function New-BashObject {
function ConvertFrom-BashArgs {

Each result is a GrepMatch with typed properties:

$matches = grep -n 'function' src/PsBash.psm1
$matches[0].FileName    # "/home/you/src/PsBash.psm1"
$matches[0].LineNumber   # 7
$matches[0].Line         # "function Get-BashPlatform {"

With multiple files, output includes the filename prefix:

grep 'Import-Module' *.ps1

profile.ps1:Import-Module PsBash
setup.ps1:Import-Module Pester

Flags

Flag	Description
-i	Case-insensitive matching
-v	Invert match (select non-matching lines)
-n	Prefix each line with its line number
-c	Print count of matching lines only
-r	Recursive search through directories
-l	Print only names of files with matches
-E	Extended regular expressions (ERE syntax)
-A NUM	Show NUM lines after each match
-B NUM	Show NUM lines before each match
-C NUM	Show NUM lines before and after each match

GrepMatch Properties

In file mode, each result is a PsBash.GrepMatch object:

Property	Type	Description
FileName	string	Absolute path to the matched file
LineNumber	int	1-based line number of the match
Line	string	Full text of the matched line
BashText	string	Formatted output string (includes filename/line number prefixes)

Tip

In pipeline mode, grep does not return GrepMatch objects. It returns whatever objects were piped in. This is what makes pipeline composition work — types survive through grep, sort, head, and tail without losing structure.

Examples

Case-insensitive search:

grep -i 'error' /var/log/app.log

Regex with extended syntax:

grep -E 'warn|error|fatal' server.log

Inverted match (exclude lines):

cat config.yml | grep -v '^#'

Count matches per file:

grep -rc 'import' src/

src/main.ps1:3
src/utils.ps1:1

Context lines around matches:

grep -B2 -A2 'throw' src/PsBash.psm1

List files containing a pattern:

grep -rl 'Invoke-BashGrep' src/

Recursive search from a directory:

grep -r 'function' src/

Pipeline bridge with further processing:

# Find large .log files -- types preserved through grep
$logs = ls -la | grep '\.log'
$logs | ForEach-Object { $_.SizeBytes } | Measure-Object -Sum

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rg

Recursive search across files, modeled after ripgrep. Searches recursively by default, skips .git directories, and excludes dotfiles unless --hidden is specified.

rg [OPTIONS] PATTERN [PATH...]

Flags

Flag	Description
-i	Case-insensitive matching
-w	Match whole words only (wraps pattern in \b...\b)
-c	Print count of matching lines only
-l	Print only names of files with matches
-n	Show line numbers (default)
-N	Suppress line numbers
-o	Print only the matched portion of each line
-v	Invert match (select non-matching lines)
-F	Treat pattern as a fixed string, not a regex
-g GLOB	Filter files by glob pattern (e.g., -g '*.ps1')
-A NUM	Show NUM lines after each match
-B NUM	Show NUM lines before each match
-C NUM	Show NUM lines before and after each match
--hidden	Include dotfiles and hidden directories

RgMatch Properties

Each result is a PsBash.RgMatch object:

Property	Type	Description
FileName	string	Absolute path to the matched file
LineNumber	int	1-based line number of the match
Line	string	Full text of the matched line
BashText	string	Formatted output string (includes filename/line number prefixes)

Note

Like grep, rg also supports pipeline mode. When objects are piped in with no file arguments, rg matches against BashText and passes through the original objects.

Examples

Search the current directory recursively:

rg 'function'

src/PsBash.psm1:7:function Get-BashPlatform {
src/PsBash.psm1:20:function New-BashObject {
src/PsBash.psm1:43:function ConvertFrom-BashArgs {

Filter by file type with glob:

rg -g '*.ps1' 'Import-Module'

Case-insensitive whole-word search:

rg -iw 'error'

Fixed string search (no regex interpretation):

rg -F '$_.Name'

Only show matched text:

rg -o '\d+\.\d+\.\d+' package.json

package.json:3:0.1.0

Context lines around matches:

rg -C3 'throw' src/

Count matches per file:

rg -c 'function' src/

src/PsBash.psm1:69
src/Help.psm1:2

List files containing a pattern:

rg -l 'Invoke-Bash'

Include hidden files:

rg --hidden 'alias' .

Suppress line numbers for clean output:

rg -N 'version' package.json

grep vs rg

	grep	rg
Recursive	Requires -r flag	Recursive by default
Dotfiles	Includes everything with -r	Excludes by default, --hidden to include
.git directory	Included with -r	Always skipped
Glob filtering	Not supported	-g '*.ext'
Only-matching	Not supported	-o flag
Fixed strings	Not supported	-F flag
Word boundaries	Not supported	-w flag
Line numbers	Off by default, -n to enable	On by default, -N to disable
Pipeline bridge	Passes original objects	Passes original objects