How can I make Powershell behave like Bash with its flag set -e
? set -o errexit
makes a Bash script \"Exit immediately if a simple command exits with a
$ErrorActionPreference
works as intended, it's just that exit codes from native programs are not nearly as well-behaved as PowerShell cmdlets.
For a cmdlet
the error condition is fairly easy to determine: Did an exception happen or not? So the following would not reach the Write-Host
statement with $ErrorActionPreference
set to Stop
:
Write-Error blah
or
Get-ChildItem somepathwhichsurelydoesntexisthere
For native programs an exit code of zero usually signals that no error occurred but that's merely a convention, as is a non-zero exit code signalling an error. Would you say that if choice
exists with an exit code of 1 that it was an error?
The only robust way to handle this is to check the exit code after running a native command and handling it yourself, if needed. PowerShell doesn't try to guess what the result meant because the conventions aren't strong enough to warrant a default behaviour in this case.
You can use a function if you want to make your life easier:
function Invoke-NativeCommand {
$command = $args[0]
$arguments = $args[1..($args.Length)]
& $command @arguments
if (!$?) {
Write-Error "Exit code $LastExitCode while running $command $arguments"
}
}
But in general many programs need different handling because they don't adhere to said convention.