Question

I have the following script which reads in a file line by line and replaces a pattern in each line with specified text, then writes this to another file:

param
(
    [string] $inFilePath,
    [string] $outFilePath,
    [string] $inputPattern,
    [string] $replacePattern
)

function Main()
{
    $sr = $null;
    $sw = $null;

    try
    {
        $sr = New-Object System.IO.StreamReader($inFilePath);
        $sw = New-Object System.IO.StreamWriter($outFilePath, $true);
        do
        {
            $fileLine = $sr.ReadLine();
            $fileLine2 = "";
            if ($fileLine -eq $null)
            {
                break;
            }
            $fileLine = $fileLine + [System.Environment]::NewLine;
            $fileLine2 = [System.Text.RegularExpressions.Regex]::Replace($fileLine, $inputPattern, $replacePattern);
            $sw.Write($fileLine2);
        }
        while ($fileLine -ne $null);
    }
    finally
    {
        $sr.Dispose();
        $sw.Dispose();
    }
}

Main;

Unfortunately, when I save the script as filereplace.ps1 and call it like this:

powershell .\filereplace.ps1 c:\docs\infile.txt c:\docs\outfile.txt '.{30,}\->.*\r\n' '*'

I get this error:

The filename, directory name, or volume label syntax is incorrect.

Any idea what I might be doing wrong? I suspect there is something wrong with the regex pattern used in searching for a replacement – when I remove the \->, it works, but there is no reason why this should be a problem.

Answer 1

It is the redirection operator > that causes the problem in the command line. Enclose the whole command with ":

powershell ".\filereplace.ps1 c:\docs\infile.txt c:\docs\outfile.txt '.{30,}\->.*\r\n' '*'"