How to send commands to running CMD instance - cmd

On Windows 10 I have a special developer command prompt (DevEnv). Every time another program (Matlab) creates a file output, I have to run a command in this command prompt to start another process:
myDevEnv.bat (sets environment variables, starts server instances, ...)
Matlab script creates myFile.foo
In DevEnv: doSomethingWithFiles.bat myFile.foo
I would like Matlab to call the third command from within the DevEnv. So my idea was to write the commands to a file, that is permanently read and executed in the DevEnv. Is this possible in a Windows command prompt?

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How can I keep powershell in repl mode with a loaded script

I'm trying to start a powershell instance, that loads a script and remains open so I can still call methods loaded by that script manually.
I'm trying to dot source a script and pipe it to powershell like below, from a cmd instance/batchfile:
echo . .\script.ps1 | powershell
The result in this case is that powershell starts, loads my script, executes it and exits. I've tried running with -noexit argument, it has no effect.
I'm thinking of another option, to start a powershell process and pipe my dot source command to its stdin - but this probably won't allow me to interact with the process anymore because its stdin is opened by the host process.
If you need to run a script file so that window stays open and variables are accessible after the execution.
Try dot sourcing the script file like this:
powershell -noexit ". .\script.ps1"
Once the script is done, you can access any internal variable the script defined. Assuming the variables are at the script level scope.

running mulitple commands using Subprocess.Popen in the same shell

Hi I am at a loss on how to run multiple commands using popen,
I am trying to automate a series of steps that are normally run on the Windows command line. The basic steps are usually run from the Windows cmd line are
Run a windows command script (.cmd) file to setup environment variables i.e C:\Program Files (x86)\appsettings\setupvariables.cmd
type in the command to connect to the database
type in the command to get data from the database
Stop connection to the database
All these commands must run in the same command line window one after another, not separate processes or separate command line windows. Instead of opening a cmd window and typing in the command I want to use python's subprocess.popen command
So far I have:
args=[]
args.append(r'C:\Program Files (x86)\appsettings\setmyvars.cmd')
args.append(r'start db on db_path="my_url"')
args.append(r'get_data_from_db>c:\temp\output.txt')
args.append(r'stop db on db_path="my_url"')
p=Popen(args,stdout=PIPE,sterr=PIPE,shell=True)
stdout,stderr=p.communicate()
if stderr:
print "you have an error", stderr
else:
print "well done you have data", stdout
This isn't quite working I can see that the first line is run i.e the setmyvars.cmd is executed, but nothing else, none of the other arguments get called, if they did I would see the results in the ouput.txt file.
How do I run a series of commands one after the other using popen. Why is it only the first command seems to be executed and none of the others
I am using python2.7 on Windows
Regards.
You have a couple of issues going on. You still have to tell popen() which program to run. Just using shell=True does not obviate the need to provide cmd.exe as the program to run. If you really want to run all of these commands with one invocation of cmd.exe, then you will need to string them together with &&.
from subprocess import *
args=[]
args.append(r'C:\Windows\System32\cmd.exe')
args.append(r'/C')
args.append(r'(echo 1 && echo 2 && echo 4)')
p = Popen(args,stdout=PIPE,stderr=PIPE,shell=True)
stdout,stderr=p.communicate()
if stderr:
print "you have an error", stderr
else:
print "well done you have data", stdout
It would probably be better to use the %ComSpec% environment variable than it would be to hardcode the location of cmd.exe. The path you have is -usually- correct. :-)

execute powershell commands with Lua

I have a program that I work with, that has an onboard lua compiler to allow for custom written actions.
Since the tool itself is very limited, especially if it goes for complex reactions over networks, I want to use Powershell over lua.
Methods like os.execute() or io.popen() use the standard command line from windows and not Powershell.
Is there a way to use Powershell with lua?
I tried to write a command line script with the Powershell editor and run this script with os.execute, but it opens it as a textfile, it would be better to write the commands directly in lua but if there is no other way, executing a Powershell script directly would also be fine. (In Windows itself you can execute the script with right mouse "click/Execute with Powershell")
-- You can generate PowerShell script at run-time
local script = [[
Write-Host "Hello, World!"
]]
-- Now create powershell process and feed your script to its stdin
local pipe = io.popen("powershell -command -", "w")
pipe:write(script)
pipe:close()
Your description of the problem makes it sound like you're using a command such as os.execute("powershellscript.ps1"), and that call invokes cmd.exe with your string as the proposed command line. Normally, Windows will open a .PS1 file for editing; this was a deliberate decision for safety. Instead, try altering the os.execute() command to explicitly call PS: os.execute("powershell.exe -file powershellscript.ps1"). If you need to pass parameters to your script, enclose them in {}. See https://msdn.microsoft.com/en-us/powershell/scripting/core-powershell/console/powershell.exe-command-line-help for more info on invoking PowerShell from the command line.

Terminal emulator implementation - problems with repeated input

I am trying to implement a terminal emulator in Java. It is supposed to be able to host both cmd.exe on Windows and bash on Unix-like systems (I would like to support at least Linux and Mac OS X). The problem I have is that both cmd.exe and bash repeat on their standard output whatever I send to their standard input.
For example, in bash, I type "ls", hit enter, at which point the terminal emulator sends the input line to bash's stdin and flushes the stream. The process then outputs the input line again "ls\n" and then the output of the ls command.
This is a problem, because other programs apart from bash and cmd.exe don't do that. If I run, inside either bash, or cmd.exe, the command "python -i", the python interactive shell does not repeat the input in the way bash and cmd.exe does. This means a workaround would have to know what process the actual output came from. I doubt that's what actual terminal emulators do.
Running "bash -i" doesn't change this behaviour. As far as I know, cmd.exe doesn't have distinct "interactive" and "noninteractive" modes.
EDIT: I am creating the host process using the ProcessBuilder class. I am reading the stdout and stderr and writing to the stdin of the process using a technique similar to the stream gobbler. I don't set any environment variables before I start the host process. The exact commands I use to start the processes are bash -i for bash and cmd for cmd.exe. I'll try to post minimal code example as soon as I manage to create one.
On Unix, run stty -echo to disable "local echo" (i.e. the shell repeating everything that you type). This is usually enabled so a user can edit what she types.
In your case, BASH must somehow allocate a pseudo TTY; otherwise, it would not echo every command. set +x would have a similar effect but then, you'd see + ls instead of ls in the output.
With cmd.exe the command #ECHO OFF should achieve the same effect.
Just execute those after the process has been created and it should work.

Install MathLink program with arbitrary PATH environment

Is it possible to use Install[] to start a MathLink program with a custom PATH environment variable?
I am trying to use mEngine to connect Mathematica to MATLAB on Windows. It only works if mEngine.exe is launched when the PATH environment variable includes the path to the MATLAB libraries. Is it possible to modify the PATH for launching this program only, without needing to modify the system path? Or is there another way to launch mEngine.exe?
#acl's solution to wrap mEngine.exe in a batch file, and temporarily modify the PATH from there, works correctly:
I used this as the contents of mEngine.bat:
set PATH=c:\path\to\matlab\bin\win32;%PATH%
start mEngine.exe %*
*% ensures that all command line arguments are passed on to mEngine.exe
start is necessary to prevent the command window from staying open until mEngine.exe terminates
It can be started using Install["mEngine.bat"].
Since all the information that is needed for the kernel to communicate with mEngine.exe is passed by Install[] as command line arguments, all we need to do is launch mEngine.exe with these arguments. It is not necessary for Install[] to know the location of mEngine.exe, the important thing is that the process gets launched with the correct command line arguments, which is ensured by %*.

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