Search for username inside a UNC path in a text file

I got a log file where I want to extract the username on a line where it says ERROR 5.

Example:

2018/04/13 10:48:04 ERROR 5 (0x00000005) Copying File \\myserver\shares\johnsmith\My Documents\examplefile.txt

I want to find the string "johnsmith" and put it in a new text file. My idea was to search for ERROR 5 and then find the string in between the fourth and the fifth "\"-letter.

I've found this while googling:

(get-content C:\temp\testlog.txt)  | % { 
    if ($_ -match "ERROR 5 (0x00000005) Copying File \\myserver\shares\ (.*)") { 
        $name = $matches[1]
        echo $name
    }
}

But doesn't really work.

Can anyone give me any clues what functions to use?

Assuming the file path is always as described, this should give you the names, files and error codes for any matching lines it finds in the log file:

Get-Content C:\temp\testlog.txt  |
    ForEach-Object { 
        if ($_ -match "^.*ERROR (?<ErrorCode>(\d+)) \(0x\d+\) Copying File \\\\myserver\\shares\\(?<UserName>\w+)\\My Documents\\(?<FileName>.*)$") 
        { 
            [PsCustomObject]@{
                UserName = $matches.UserName;
                FileName = $matches.FileName;
                ErrorCode = $matches.ErrorCode
        }
    }
}

Output looks like this:

UserName  FileName        ErrorCode
--------  --------        ---------
johnsmith examplefile.txt 5        
marysmith examplefile.txt 5        
adamsmith examplefile.txt 5        
philsmith examplefile.txt 5 

To capture just the user names to file, modify the code to this:

Get-Content .\testlog.txt  |
    ForEach-Object { 
        if ($_ -match "^.*ERROR (?<ErrorCode>(\d+)) \(0x\d+\) Copying File \\\\myserver\\shares\\(?<UserName>\w+)\\.*$") 
        { 
            $matches.UserName
        }
    } | Out-File .\UserNames.txt