Powershell to match the current line and next line then out-file - powershell

Question

I'm trying to extract the data whereby:
line 1 = Report ID + Line 2 = "Machine no" + Line 3 = OFFLINE
Then Out-File to a new file.
Sample data
Report ID page1
Machine no 1234
OTHERS
12
offline
12
OTHERS
23
offline
37
OTHERS
89
offline
65
The result I'm looking for look something like the below after processing:
Report ID page 4
Machine no 1234
offline
12
offline
37
offline
65

Answer 1

You can use the Select-String cmdlet with the -Context Parameter to search through a file and then select how many lines of contextual info you want to get back from your search.
For instance, if we take your input file and store it in a variable called $input like so:
$inputFile= Get-Content C:\Path\To\YourFile.txt
$inputFile| Select-string 'machine no'
>Machine no 1234
We can then find matches for the phrase 'offline' with this:
$inputFile| Select-String offline -Context 0,1
This states that I want you to search for the word 'offline' and give me zero lines proceeding it, and one line after it, giving us this output:
> offline
12
> offline
37
> offline
65
We can put this all together to build this and generate a new output file that would look like this.
$out= ''
$out += $inputFile| Select-string 'machine no'
$out += "`n"
$out += $inputFile| Select-String offline -Context 0,1 | ForEach-Object {$_.Context.DisplayPostContext}
#Resulting file would look this, just the name of the machine and then the number of each offline...uh, whatever it is.
Machine no 1234
12 37 65
If I were you, I'd adapt this flow to make PowerShell objects and properties instead, like this:
$Report = [pscustomobject]#{ID='';MachineNo='';OfflineMembers=#()}
$Report.ID = ($inputFile | select-string page -Context 0 ).ToString().Split('page')[-1]
$Report.MachineNo = ($inputFile | Select-string 'machine no').ToString().Trim().Split()[-1]
$Report.OfflineMembers = $inputFile | Select-String offline -Context 0,1 | ForEach-Object {
[pscustomobject]#{Value='Offline';ID=$_.Context.DisplayPostContext.Trim()}
}
>$Report
ID MachineNo OfflineMembers
-- --------- --------------
1 1234 {#{Value=Offline; ID=12}, #{Value=Offline; ID=37}, #{Value=Offline; ID=65}}
$Report.OfflineMembers
Value ID
----- --
Offline 12
Offline 37
Offline 65