I'm getting unsure why executeShell works on the pause command, but cls that is responsible for clearing the text do not.

import std.stdio, std.process;
void main()
{
	writeln("Some text that will appear in cmd");
	executeShell("cls"); // Does not clear the text?
	executeShell("pause"); // Pauses the cmd.exe to keep from closing itself.
}

On Tuesday, 21 May 2019 at 07:16:29 UTC, Boqsc wrote:
> I'm getting unsure why executeShell works on the pause command, but cls that is responsible for clearing the text do not.
>
> import std.stdio, std.process;
> void main()
> {
> 	writeln("Some text that will appear in cmd");
> 	executeShell("cls"); // Does not clear the text?
> 	executeShell("pause"); // Pauses the cmd.exe to keep from closing itself.
> }

As far as I understand [1], executeShell starts a new shell and executes %command% in that shell. So cls wouldn't be called in the shell where you wrote Some text...

[1] https://dlang.org/phobos/std_process.html#.executeShell

try next:
spawnShell( "cls" ).wait;

On Tuesday, 21 May 2019 at 10:03:38 UTC, KnightMare wrote:
> try next:
> spawnShell( "cls" ).wait;

Wow, spawnShell indeed does the job as I would expect, as of right now. Thanks.

spawnShell Function indeed sounds like it would spawn a new shell instead of what it does, at first I didn't look into it very seriously while checking documentation.
https://dlang.org/library/std/process/spawn_shell.html

On Tuesday, 21 May 2019 at 07:16:29 UTC, Boqsc wrote:
> I'm getting unsure why executeShell works on the pause command, but cls that is responsible for clearing the text do not.

When you ran pause, did it print the text "press any key to continue"?

executeShell captures the output of the program, so I'm guessing no. And that is why cls does nothing - its output is captured into a string instead of displayed on screen.

spawnShell keeps the output connected unless you ask it not to.
http://dpldocs.info/experimental-docs/std.process.spawnShell.1.html

On Tuesday, 21 May 2019 at 12:51:41 UTC, Adam D. Ruppe wrote:
> On Tuesday, 21 May 2019 at 07:16:29 UTC, Boqsc wrote:
>> I'm getting unsure why executeShell works on the pause command, but cls that is responsible for clearing the text do not.
>
> When you ran pause, did it print the text "press any key to continue"?
>
You are absolutely correct.
There was no output, it was captured, as executeShell is used for capturing command output.

auto commandOutput = executeShell("pause");
writeln("Here is the output: ", commandOutput);
// Here is the output:  Tuple!(int, "status", string, "output")(0, "Press any key to continue . . . \r\n")

> executeShell captures the output of the program, so I'm guessing no. And that is why cls does nothing - its output is captured into a string instead of displayed on screen.
>
> spawnShell keeps the output connected unless you ask it not to.
> http://dpldocs.info/experimental-docs/std.process.spawnShell.1.html

Thanks for summarising.