Delete all text after string...

Question

I have a series of text files that I am attempting to parse with PowerShell. I haven't done much with text file manipulation and would love some advice. Thanks in advance to anyone willing to give this a go!
Example File: (file name = "report_20131231.txt")
**** SAMPLE1 ****
user1 username1
user2 username2
user3 username3
**** SAMPLE2 ****
user4 username4
user5 username5
user6 username6
I want to import the text file and reformat it to the following:
Date | SAMPLE # | Username
<file name date> | <sample #> | <username>
Example Output:
Date | SAMPLE # | Username
20131231 | SAMPLE 1 | username1
20131231 | SAMPLE 1 | username2
20131231 | SAMPLE 1 | username3
20131231 | SAMPLE 2 | username4
20131231 | SAMPLE 2 | username5
20131231 | SAMPLE 2 | username6

Answer 1

This code seems to work for parsing your original file format:
function Import-YourSampleFile
[CmdletBinding()]
param (
[Parameter(Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true)]
[Alias('FullName', 'PSPath')]
[string[]]
$Path
process
foreach ($string in $Path)
if ($string -match '(\d{4})(\d{2})(\d{2})(?:\.[^\.]*)?$')
$date = Get-Date -Year $matches[1] -Month $matches[2] -Day $matches[3] -Format yyyyMMdd
else
$date = 'Unknown'
$sampleNumber = $null
Get-Content -Path $string |
ForEach-Object {
$line = $_
switch -Regex ($line)
'^\s*\*{4}\s*SAMPLE(\d+)\s*\*{4}\s*$'
$sampleNumber = $matches[1]
break
'^\s*\S+\s+(\S+)\s*$'
if ($null -ne $sampleNumber)
New-Object psobject -Property @{
Date = $date
Sample = "SAMPLE $sampleNumber"
UserName = $matches[1]
break
} # ForEach-Object
} # foreach ($string in $Path)
} # process
} # function Import-YourSampleFile
The rest is just using this function in conjunction with Export-Csv (or something very like it) to produce the pipe-separated format you wanted.  Something like this:
Get-ChildItem -Path .\report_*.txt |
Import-YourSampleFile |
Export-Csv .\output.txt -NoTypeInformation -Delimiter '|'