conditional execution (&& and ||) in powershell

2019: the Powershell team are considering adding support for && to Powershell - weigh in at this GitHub PR

Try this:

$(command -arg1 -arg2 | Out-Host;$?) -and $(command2 -arg1 | Out-Host;$?)

The $() is a subexpression allowing you to specify multiple statements within including a pipeline. Then execute the command and pipe to Out-Host so you can see it. The next statement (the actual output of the subexpression) should output $? i.e. the last command's success result.

The $? works fine for native commands (console exe's) but for cmdlets it leaves something to be desired. That is, $? only seems to return $false when a cmdlet encounters a terminating error. Seems like $? needs at least three states (failed, succeeded and partially succeeded). So if you're using cmdlets, this works better:

$(command -arg1 -arg2 -ev err | Out-Host;!$err) -and 
$(command -arg1 -ev err | Out-Host;!$err)

This kind of blows still. Perhaps something like this would be better:

function ExecuteUntilError([scriptblock[]]$Scriptblock)
{
    foreach ($sb in $scriptblock)
    {
        $prevErr = $error[0]
        . $sb
        if ($error[0] -ne $prevErr) { break }
    }
}

ExecuteUntilError {command -arg1 -arg2},{command2-arg1}

Powershell 7 preview 5 has them. I don't know why this was deleted with no notification or explanation. https://devblogs.microsoft.com/powershell/powershell-7-preview-5/ This will give the output of both commands, as the question requested.

echo 'hello' && echo 'there'
hello
there

echo 'hello' || echo 'there'
hello

To simplify multistep scripts where doThis || exit 1 would be really useful, I use something like:

function ProceedOrExit { 
    if ($?) { echo "Proceed.." } else { echo "Script FAILED! Exiting.."; exit 1 } 
}

doThis; ProceedOrExit
doNext

# or for long doos
doThis
ProceedOrExit
doNext

With Powershell 7.0 released, && and || are supported

https://devblogs.microsoft.com/powershell/announcing-powershell-7-0/

New operators:
  Ternary operator: a ? b : c
  Pipeline chain operators: || and &&
  Null coalescing operators: ?? and ??=