In powershell, i want Ioop twice through a text file but in second loop i want to continue from end of first loop - powershell

Question

I have a text file to process. Text file has some configuration data and some networking commands. I want to run all those network commands and redirect output in some log file.
At starting of text file,there are some configuration information like File-name and file location. This can be used for naming log file and location of log file. These line starts with some special characters like '<#:'. just to know that rest of the line is config data about file not the command to execute.
Now, before i want start executing networking commands (starts with some special characters like '<:'), first i want to read all configuration information about file i.e. file name, location, overwrite flag etc. Then i can run all commands and dump output into log file.
I used get-content iterator to loop over entire text file.
Question: Is there any way to start looping over file from a specific line again?
So that i can process config information first (loop till i first encounter command to execute, remember this line number), create log file and then keep running commands and redirect output to log file (loop from last remembered line number).
Config File looks like:
<#Result_File_Name:dump1.txt
<#Result_File_Location:C:\powershell
<:ping www.google.com
<:ipconfig
<:traceroute www.google.com
<:netsh interface ip show config
My powerhsell script looks like:
$content = Get-Content C:\powershell\config.txt
foreach ($line in $content)
{
if($line.StartsWith("<#Result_File_Name:")) #every time i am doing this, even for command line
{
$result_file_arr = $line.split(":")
$result_file_name = $result_file_arr[1]
Write-Host $result_file_name
}
#if($line.StartsWith("<#Result_File_Location:"))#every time i am doing this, even for command line
#{
# $result_file_arr = $line.split(":")
# $result_file_name = $result_file_arr[1]
#}
if( $conf_read_over =1)
{
break;
}
if ($line.StartsWith("<:")) #In this if block, i need to run all commands
{
$items = $line.split("<:")
#$items[0]
#invoke-expression $items[2] > $result_file_name
invoke-expression $items[2] > $result_file_name
}
}

Answer 1

If all the config information starts with <# just process those out first separately. Once that is done you can assume the rest are commands?
# Collect config lines and process
$config = $content | Where-Object{$_.StartsWith('<#')} | ForEach-Object{
$_.Trim("<#") -replace "\\","\\" -replace "^(.*?):(.*)" , '$1 = $2'
} | ConvertFrom-StringData
# Process all the lines that are command lines.
$content | Where-Object{!$_.StartsWith('<#') -and ![string]::IsNullOrEmpty($_)} | ForEach-Object{
Invoke-Expression $_.trimstart("<:")
}
I went a little over board with the config section. What I did was convert it into a hashtable. Now you will have your config options, as they were in file, accessible as an object.
$config
Name Value
---- -----
Result_File_Name dump1.txt
Result_File_Location C:\powershell
Small reconfiguration of your code, with some parts missing, would look like the following. You will most likely need to tweak this to your own needs.
# Collect config lines and process
$config = ($content | Where-Object{$_.StartsWith('<#')} | ForEach-Object{
$_.Trim("<#") -replace "\\","\\" -replace "^(.*?):(.*)" , '$1 = $2'
} | Out-String) | ConvertFrom-StringData
# Process all the lines that are command lines.
$content | Where-Object{!$_.StartsWith('<#') -and ![string]::IsNullOrEmpty($_)} | ForEach-Object{
Invoke-Expression $_.trimstart("<:") | Add-Content -Path $config.Result_File_Name
}

Answer 2

As per your comment you are still curious about your restart loop logic which was part of your original question. I will add this as a separate answer to that. I would still prefer my other approach.
# Use a flag to determine if we have already restarted. Assume False
$restarted = $false
$restartIndexPoint = 4
$restartIndex = 2
for($contentIndex = 0; $contentIndex -lt $content.Length; $contentIndex++){
Write-Host ("Line#{0} : {1}" -f $contentIndex, $content[$contentIndex])
# Check to see if we are on the $restartIndexPoint for the first time
if(!$restarted -and $contentIndex -eq $restartIndexPoint){
# Set the flag so this does not get repeated.
$restarted = $true
# Reset the index to repeat some steps over again.
$contentIndex = $restartIndex
}
}
Remember that array indexing is 0 based when you are setting your numbers. Line 20 is element 19 in the string array for example.
Inside the loop we run a check. If it passes we change the current index to something earlier. The write-host will just print the lines so you can see the "restart" portion. We need a flag to be set so that we are not running a infinite loop.