Pulling a substring for each line in file

Question

Using Powershell, I am simply trying to pull 15 characters starting from the 37th position of any record that begins with a 6. I'd like to loop through and generate a record for each instance so it can later be put into an output file. But I seem to not be hitting the correct syntax just to return the 15 characters I know I am missing something obvious. Been at this for a while. Here is my script:

$content = Get-Content -Path .\tmfhsyst*.txt | Where-Object { $_.StartsWith("6") }

foreach ($line in $contents) 
{
  $val102 = $line.substring(36,15)
}

write-output $val102

Answer 1

Just as Bill_Stewart pointed out, you need to move your Write-Output line inside the ForEach loop. A possibly better way to do it would just be to pipe it:

Get-Content -Path .\tmfhsyst*.txt | Where-Object { $_.StartsWith("6") } | foreach{$_.substring(36,15)}

That should give you the output you desired.

Answer 2

Using Substring() has the disadvantage that it will raise an error if the string is shorter than start index + substring length. You can avoid this with a regular expression match:

(Get-Content -Path .\tmfhsyst*.txt) -match '^6.{35}(.{15})' | % { $matches[1] }