This is Line 1
This is Line 2
This is Line 3
This is Line 4: Here is the line with my keyword
This is Line 5
This is Line 6

$InputFilePath = "C:\Users\<username>\Desktop\Test.txt"
$InputKeyword  = "keyword"

$Line = Select-String -Pattern $InputKeyword -SimpleMatch -Path $InputFilePath 

$Line

Desktop\Test.txt:4:This is Line 4: Here is the line with my keyword

Desktop\Test.txt:4:This is Line 4: Here is the line with my keyword
Desktop\Test.txt:7:This is Line 7: Here is another line with my keyword

############################################################################################################  
#
#  get_line_in_file - Returns line in a file if matched by a regex
#
#  Params:  source_file      - The source file (req'd)
#           regex            - The pattern to match
#           firstMatchOnly   - Y for the first match only
#
#  Output:  The first occurrence of the line or part of line to match if found, NULL if no match
#
#  Notes:   Uses streams so file is not read into memory, unlike Get-Content
#
#           The regex param must be constructed so what you want returned is enclosed
#           in parens, as that is Groups[1]. This is so just a part of the matched line can be 
#           returned if that is what is needed.
#           (.*CONTRACT_TYPE.*) - The entire line will be returned if it contains the text CONTRACT_TYPE.
#           ^ *(.*),.*CONTRACT_TYPE - The text after 0 or more spaces and before the first comma will be
#                                     returned on the first line that contains the text CONTRACT_TYPE.
#
#  Usage in VC: Powershell file: {USERVAR(EnvBinDir)}\get_line_line_in_file.ps1
#               Working directory: <leave blank>
#
#  Author: Gary_W  01/03/2019
#
############################################################################################################   
Param(
  [Parameter(Mandatory=$true)]
  [string] $source_file,             # Source file

  [Parameter(Mandatory=$true)]
  [string] $regex,                   # Regular expression

  [Parameter(Mandatory=$true)]       # Y to return only the first match,
  [string] $firstMatchOnly           # N to return all matches

)

#
#  Loop through the source file
#

$match = $null

$file = New-Object System.IO.StreamReader($source_file, [Text.Encoding]::default, $true, 1MB)  
:main while (!$file.EndOfStream) {
   $line = $file.Readline()
   $match = [regex]::match($line, $regex).Groups[1].Value
   if ( ! [string]::IsNullOrEmpty($match) ) 
   {
     $match  # Print it to STDOUT
     
     if ( $firstMatchOnly.ToUpper() -eq 'Y' )
     {
       break main
     }
   }
}
$file.Close()
$file.Dispose()

##  End get_line_in_file()