PsExec Throws Error Messages, but works without any problems

Question

So we are using PsExec a lot in our automations to install virtual machines, as we can\'t use ps remote sessions with our windows 2003 machines. Everything works great and t

Answer 1

I have created a psexec wrapper for powershell, which may be helpful to people browsing this question:

function Return-CommandResultsUsingPsexec {
    param(
        [Parameter(Mandatory=$true)] [string] $command_str,
        [Parameter(Mandatory=$true)] [string] $remote_computer,
        [Parameter(Mandatory=$true)] [string] $psexec_path,
        [switch] $include_blank_lines
    )

    begin {
        $remote_computer_regex_escaped = [regex]::Escape($remote_computer)

        # $ps_exec_header = "`r`nPsExec v2.2 - Execute processes remotely`r`nCopyright (C) 2001-2016 Mark Russinovich`r`nSysinternals - www.sysinternals.com`r`n"

        $ps_exec_regex_headers_array = @(
            '^\s*PsExec v\d+(?:\.\d+)? - Execute processes remotely\s*$',
            '^\s*Copyright \(C\) \d{4}(?:-\d{4})? Mark Russinovich\s*$',
            '^\s*Sysinternals - www\.sysinternals\.com\s*$'
        )

        $ps_exec_regex_info_array = @(
            ('^\s*Connecting to ' + $remote_computer_regex_escaped + '\.{3}\s*$'),
            ('^\s*Starting PSEXESVC service on ' + $remote_computer_regex_escaped + '\.{3}\s*$'),
            ('^\s*Connecting with PsExec service on ' + $remote_computer_regex_escaped + '\.{3}\s*$'),
            ('^\s*Starting .+ on ' + $remote_computer_regex_escaped + '\.{3}\s*$')
        )

        $bypass_regex_array = $ps_exec_regex_headers_array + $ps_exec_regex_info_array

        $exit_code_regex_str = ('^.+ exited on ' + $remote_computer_regex_escaped + ' with error code (\d+)\.\s*$')

        $ps_exec_args_str = ('"\\' + $remote_computer + '" ' + $command_str)
    }

    process {
        $return_dict = @{
            'std_out' = (New-Object 'system.collections.generic.list[string]');
            'std_err' = (New-Object 'system.collections.generic.list[string]');
            'exit_code' = $null;
            'bypassed_std' = (New-Object 'system.collections.generic.list[string]');
        }

        $process_info = New-Object System.Diagnostics.ProcessStartInfo
        $process_info.RedirectStandardError = $true
        $process_info.RedirectStandardOutput = $true
        $process_info.UseShellExecute = $false
        $process_info.FileName = $psexec_path
        $process_info.Arguments = $ps_exec_args_str

        $process = New-Object System.Diagnostics.Process
        $process.StartInfo = $process_info
        $process.Start() | Out-Null

        $std_dict = [ordered] @{
            'std_out' = New-Object 'system.collections.generic.list[string]';
            'std_err' = New-Object 'system.collections.generic.list[string]';
        }

        # $stdout_str = $process.StandardOutput.ReadToEnd()
        while ($true) {
            $line = $process.StandardOutput.ReadLine()
            if ($line -eq $null) {
                break
            }
            $std_dict['std_out'].Add($line)
        }

        # $stderr_str = $process.StandardError.ReadToEnd()
        while ($true) {
            $line = $process.StandardError.ReadLine()
            if ($line -eq $null) {
                break
            }
            $std_dict['std_err'].Add($line)
        }

        $process.WaitForExit()

        ForEach ($std_type in $std_dict.Keys) {
            ForEach ($line in $std_dict[$std_type]) {
                if ((-not $include_blank_lines) -and ($line -match '^\s*$')) {
                    continue
                }

                $do_continue = $false
                ForEach ($regex_str in $bypass_regex_array) {
                    if ($line -match $regex_str) {
                        $return_dict['bypassed_std'].Add($line)
                        $do_continue = $true
                        break
                    }
                }
                if ($do_continue) {
                    continue
                }

                $exit_code_regex_match = [regex]::Match($line, $exit_code_regex_str)

                if ($exit_code_regex_match.Success) {
                    $return_dict['exit_code'] = [int] $exit_code_regex_match.Groups[1].Value
                } elseif ($std_type -eq 'std_out') {
                    $return_dict['std_out'].Add($line)
                } elseif ($std_type -eq 'std_err') {
                    $return_dict['std_err'].Add($line)
                } else {
                    throw 'this conditional should never be true; if so, something was coded incorrectly'
                }
            }
        }

        return $return_dict
    }
}