Assuming you wanted to grab the info from a SQL Server install log - specifically the Exit Code, here's some terrible PowerShell to do so

InstallLogparser.ps1

# Sample data of what Summary.txt looks like
<#
Overall summary:
  Final result:                  Passed
  Exit code (Decimal):           0
  Start time:                    2021-02-26 03:03:25
  End time:                      2021-02-26 03:04:36
  Requested action:              Patch

Instance DEV2019UTF8 overall summary:
  Final result:                  Passed
  Exit code (Decimal):           0
  Start time:                    2021-02-26 03:03:48
  End time:                      2021-02-26 03:04:32
  Requested action:              Patch
...
#>
$logLocation = "C:\Program Files\Microsoft SQL Server\150\Setup Bootstrap\Log\Summary.txt"
$regex = "Exit code \(Decimal\):\s+(\d)"
$output = Select-String -Path $logLocation -Pattern $regex

foreach ($match in $output.Matches)
{
    #Group 0 is the text before the match code, group 1 is the named match
    if ($match.Success)
    {
        Write-Output $match.Groups[1].Captures[0].Value
        break
    }
}

# or try and use this godawful mess
# Find the line with Exit code (there can be multiples). 
# Grab the first one and only get the Line property
$firstMatch = Select-String -Path $logLocation -Pattern "Exit code (Decimal)" -SimpleMatch | Select-Object -Property Line -First 1 
# Split the resulting line on the colon and take the second half and strip off whitespace
$finalValue = ($firstMatch.Line -split ":")[1].trim()
Write-Output $finalValue