How to output something in PowerShell

I think the following is a good exhibit of Echo vs. Write-Host. Notice how test() actually returns an array of ints, not a single int as one could easily be led to believe.

function test {
    Write-Host 123
    echo 456 # AKA 'Write-Output'
    return 789
}

$x = test

Write-Host "x of type '$($x.GetType().name)' = $x"

Write-Host "`$x[0] = $($x[0])"
Write-Host "`$x[1] = $($x[1])"

Terminal output of the above:

123
x of type 'Object[]' = 456 789
$x[0] = 456
$x[1] = 789

I think in this case you will need Write-Output.

If you have a script like

Write-Output "test1";
Write-Host "test2";
"test3";

then, if you call the script with redirected output, something like yourscript.ps1 > out.txt, you will get test2 on the screen test1\ntest3\n in the "out.txt".

Note that "test3" and the Write-Output line will always append a new line to your text and there is no way in PowerShell to stop this (that is, echo -n is impossible in PowerShell with the native commands). If you want (the somewhat basic and easy in Bash) functionality of echo -n then see samthebest's answer.

If a batch file runs a PowerShell command, it will most likely capture the Write-Output command. I have had "long discussions" with system administrators about what should be written to the console and what should not. We have now agreed that the only information if the script executed successfully or died has to be Write-Host'ed, and everything that is the script's author might need to know about the execution (what items were updated, what fields were set, et cetera) goes to Write-Output. This way, when you submit a script to the system administrator, he can easily runthescript.ps1 >someredirectedoutput.txt and see on the screen, if everything is OK. Then send the "someredirectedoutput.txt" back to the developers.

Simply outputting something is PowerShell is a thing of beauty - and one its greatest strengths. For example, the common Hello, World! application is reduced to a single line:

"Hello, World!"

It creates a string object, assigns the aforementioned value, and being the last item on the command pipeline it calls the .toString() method and outputs the result to STDOUT (by default). A thing of beauty.

The other Write-* commands are specific to outputting the text to their associated streams, and have their place as such.