Replace next two lines after string match - regex

Question

I´m currently working on a script that should based on user´s choice replace two lines in a file after a matching string.
The file I want to edit looks like this:
[default]
string_a=sadasdasdas
string_b=dasdasdasdas
[profile1]
string_a=xxxxxx
string_b=xsaassaasas
[profile2]
string_a=yyyyyyy
string_b=yaayayayaya
I want always to override string_a & string_b after [default].
Note that [default] could also be at the very bottom of the file, therefore I cannot just count lines an do it that static.
The user can pick between (in this case) profile 1 & profile 2. After he picked e.g profile 2, string_a & string_b of profile2 should be replaced with string_a & string_b of default.
My current code like like this:
$filePath = './credentials'
$fileContent = Get-Content $filePath
$profiles = [regex]::Matches($fileContent, '\[(.*?)\]') |ForEach-Object { $_.Groups[1].Value }
Write-Host "Following profiles found: "
for ($i=0; $i -lt $profiles.length; $i++){
Write-Host $i"." $profiles[$i]
}
$userInput = Read-Host "Which profile set to default? "
Write-Host $profiles[$userInput]
$fileContent | Select-String $profiles[$userInput] -Context 1,2 | ForEach-Object {
$stringA = $_.Context.PostContext[0]
$stringB = $_.Context.PostContext[1]
#At this point I have access to the both string´s I want to replace the string´s of the default profile
# I could do this, but then I still have the old lines in the file...
# So the following code is not an option.
$NewContent = Get-Content -Path $filePath |
ForEach-Object {
# Output the existing line to pipeline in any case
$_
# If line matches regex
if($_ -match ('^' + [regex]::Escape('[default]')))
{
# Add output additional line
$stringA
$stringB
}
}
# Write content of $NewContent varibale back to file
$NewContent | Out-File -FilePath $filePath -Encoding Default -Force
}
Example output file, in case the user picked profile1 as the new default
[default]
string_a=xxxxxx
string_b=xsaassaasas
[profile1]
string_a=xxxxxx
string_b=xsaassaasas
[profile2]
string_a=yyyyyyy
string_b=yaayayayaya
Hope this is not obvious, but as it is my first real powershell script I was not able to find a solution for my problem yet.
Any help would be great!
Thanks

Answer 1

Example:
# This is sample data
$lines = #(#'
[default]
string_a=sadasdasdas
string_b=dasdasdasdas
[profile1]
string_a=xxxxxx
string_b=xsaassaasas
[profile2]
string_a=yyyyyyy
string_b=yaayayayaya
'# -split "`r`n")
# In real world use:
# $encoding = [System.Text.Encoding]::ASCII
# $lines = [System.IO.File]::ReadAllLines($path, $encoding)
#Read file
$lines = $lines | ForEach-Object { $_.Trim()} # Trim spaces
$sections = #{}
$currentSection = $null
$hasErrors = $false
$lines | ForEach-Object {
if ([String]::IsNullOrWhiteSpace($_)) {
#ignore
} elseif ($_.StartsWith('[') -and $_.EndsWith(']') ) {
$currentSection = $_.Substring($_.IndexOf('[') + 1, $_.LastIndexOf(']') - 1)
$sections[$currentSection] = #{}
} elseif ($sections.ContainsKey($currentSection)) {
$PVPair = [String[]]$_.Split('=',2)
if ($PVPair.Count -eq 2) {
$sections[$currentSection][$PVPair[0]] = $PVPair[1]
} else {
Write-Warning -Message "Wrong line format [$($_)]"
$hasErrors = $true
}
} else {
Write-Warning -Message "Unexpected behaviour on section $currentSection, line $($_)"
$hasErrors = $true
}
}
if ($hasErrors) {
Write-Error -Message 'Errors occured'
return
}
# Choice
$choice = $null
$choiceVariants = #($sections.Keys | Where-Object { $_ -ne 'default' })
while ($choiceVariants -notcontains $choice) {
Write-Host "Choose between $($choiceVariants -join ',')"
$choice = $choiceVariants | Out-GridView -Title 'Choose variant' -OutputMode Single
#Alternative: $choice = Read-Host -Prompt "Your choice"
}
Write-Host -ForegroundColor Yellow "You choose $($choice)"
# Change
$sections[$choice]['string_a'] = $sections['default']['string_a']
$sections[$choice]['string_b'] = 'newXSAA'
# Output
$outputLines = $sections.Keys | ForEach-Object {
$sectionName = $_
Write-Output "[$sectionName]"
$sections[$sectionName].Keys | ForEach-Object {
Write-Output "$_=$($sections[$sectionName][$_])"
}
}
# This is sample output
$outputLines | % { Write-Host $_ -f Magenta }
# In Real world:
# [System.IO.File]::WriteAllLines($path, $outputLines, $encoding)