Run .bat file from powershell

Question

I am trying to run a batch file from powershell. I would like to get the response but it is failing. If I run the .bat file:

rabbitmqctl.bat -n rabbit@xxx-123 ping

I get the following response:

Ping succeeded

However when I run it through powershell:

$test = Start-Process -FilePath "C:\Program Files\RabbitMQ\rabbitmq_server-3.10.7\sbin\rabbitmqctl.bat" -WindowStyle Hidden -ArgumentList "-n rabbit@xxx-123 ping"  -Wait -PassThru;

$test variable is empty.

Any help?

Answer 1

• To synchronously execute console applications or batch files in the current console window, call them directly.

  • This allows you to capture their output directly and to query their exit code via automatic $LASTEXITCODE variable.

• Do not use Start-Process (or the System.Diagnostics.Process API it is based on), except if truly necessary.

  • Specifically, you can not directly capture the output from an executable launched from a Start-Process call; the only in-memory output you can capture - assuming you use the -PassThru switch - is a System.Diagnostics.Process instance describing the launched process.

  • GitHub docs issue #6239 provides guidance on when use of Start-Process is and isn't appropriate.

Therefore:

$test = 
  & 'C:\Program Files\RabbitMQ\rabbitmq_server-3.10.7\sbin\rabbitmqctl.bat' -n rabbit@xxx-123 ping

Note:

• Generally, you can call executables and batch files with arguments as you would from cmd.exe, though there are some PowerShell-specific requirements:

  • Because your specific batch-file path requires quoting, use of &, the call operator, is needed (you may choose to always use it, but it is only necessary for commands (executable paths) that are quoted and/or contain variable references.

  • For executables / batch files located in the current directory, a notable difference between cmd.exe and PowerShell is that the latter - by security-minded design - requires your to explicitly signal the intent to invoke the file there, using prefix .\ (or ./); e.g. while cmd.exe allows you to use rabbitmqctl.bat to invoke a batch file by that name in the current directory, PowerShell requires .\rabbitmqctl.bat

  • PowerShell's variable references, string literals and escaping rules differ from cmd.exe:

    • PowerShell supports two kinds of quoted string literals, expandable (double-quoted) strings ("...") and verbatim (single-quoted) strings ('...')

    • PowerShell's escape character is `, the so-called backtick, where cmd.exe uses ^

    • Variable references in PowerShell use sigil $ and distinguish between PowerShell-only and environment variables (e.g, $foo and $env:USERPROFILE), compared to cmd.exe, which knows only environment variables and uses %...% syntax (e.g. %USERPROFILE%)

    • Compared to cmd.exe, PowerShell has different and more metacharacters (characters with special meaning), notably $ @ { } , ; ( ) `. These enable many advanced features.