(xpost from superuser with no answers.)
I am trying to reconfigure a known (virtual?) com port on multiple computers on a local network using a batch file.
A USB device we use is installed always as com9 and always comes in as default 9600 baud, and we have to manually reconfigure each station to 57600 baud.
I already have this batch file renaming printers, dns servers, Killing and starting tasks, copying files and a whole lot more, I've experimented with mode, but I'm either not using it properly or it can't do what I want.
I know I can use the GUI, but for the sake of speed, I want the batch to do it.
Sorry if this is a copy, but I'm seeing if anyone has an angle for me, I'm not afraid of personal research, but I'm running into dead ends with no leads.
Ask if you need any clarifications, and thanks in advance.
Powershell is okay too if I know what I need and can still stay in the cmd environment.
Related
I want to use Postgresql in Windows Server 2012 R2 for one our project where it can be 24/7 uptime.
I would like to ask the community if I can have 2 master instances in 2 different servers A&B and they will 'work' on the same DB located in a shared file storage in lan. Always one master instance on server A will be online and when it goes offline for some reason (I suppose) a powershell script will recognize that the postgresql service stopped and will start the service in server B. The same script will continuous check that only one service in servers A & B is working to avoid conflicts.
I'd like to ask if this is possible or a better approach for my configuration.
(I can't use replication because when server A shuts down the server B is in read-only mode thing that I don't want)
If you manage to start two instances of PostgreSQL on the same data directory, serious data corruption will happen.
Normally there is a postmaster.pid file that prevents that, but a PostgreSQL server process on a different machine that accesses the same file system will happily unlink that after spewing some log messages, thinking it was left behind from a crash.
So you are really walking on thin ice with a solution like that.
One other issue that you didn't think of is that script that is supposed to check if the server is still running. What if that script fails, because for example the network connection between the two servers is down, but the server is still up an running happily? Such a “split brain” scenario will cause data corruption with your setup.
Another word of caution: since you seem to be using Windows (Powershell?), you probably envision a CIFS file system when you are talking of shared storage. A Windows “network share” is not a reliable file system — last time I checked, it did not honor _commit.
Creating a reliable failover cluster is harder than you think, and I'd recommend that you check existing solutions before you try to roll your own.
I want to automate test using powershell. I want to write a script to shutdown the computer, wait for 3minutes and then power on the computer. Is it possible using Powershell? I know that reboot is possible, but I want the system to remain in shutdown stage for 3min and then power on.
If you mean a "real computer" (not a Virtual Machine) so it's not possible. But you can achieve that using Virtual Machine setup. Take look at this documentation: https://technet.microsoft.com/en-us/library/hh848589.aspx
You can shutdown computer with Stop-Computer command
Wait with Start-Sleep
But to poweron PC you need something more complex, take a look at WOL. However there are some difficulties:
It would work only with PCs that allow to be awakened with magic packets
You need to know MAC-address of machine
Target machine should be in the current network subnet of the caller.
I've got a batch file dmx2vlc which will play a random video file through VLC-Player when called.
It works well locally but I need this to happen on another machine on the network (will be adhoc) and the result (VLC-Player playing the video) must be visible on the remote screen.
I've tried SSH, Powershell and PsExec, but both seem to run the batch file and the player in the session of the command line, even when applying a patch to allow multiple logins.
So IF I get to run the batch file it is never visible on screen.
Using Teamviewer and the like is no option as I need to be able to call all this programmatically from my dmx program.
I'm not bound to being able to call the batch directly, it would be sufficient for me if I could somehow trigger it to run.
Sadly latency is a problem here as we are talking about a lighting (thus dmx) environment.
Any hints would be greatly appreciated!
You can use PSexec if the remote system is XP with the interactive parameter if you state the session to interact with, 0 would probably be the console (person physically in front of the machine).
This has issues with Windows Vista and newer as it pops up a prompt to ask the user to change their display mode first.
From memory, you could create a scheduled task on the remote system pretty easily though and as long as it's interactive the user should see it.
Good luck.
Try using web interface. It is rather easy: VLC is running http server, and accessing particular URL from remote machine will give full control over VLC. Documentation can be found here
Lets say I have an Emacs-Server running on some remote server, with all the libraries and software necessary for running my application.
Then I want several clients to connect to that remote machine, using Emacs-client. Does each client need a full Emacs installation, or is there a minimal installation that is just enough to communicate with the remote server, where all the action is?
Could this (Emacs-)client installation be so minimal, that almost all software-updates can be done on the server, without affecting the Emacs-clients?
Is there a reason not to run the clients remotely as well, and simply use a local display? That way, pretty much all you need on the local machines is the ssh client and the X Window server.
ssh -X (user)#(server) "emacsclient -c"
Edits for the comments:
This command starts a new client to connect to an existing Emacs server (which it assumes is already running). You can use "emacsclient -a '' -c" to automatically start emacs --daemon if there is no existing server, but I don't know whether you want the connecting user to be starting the server.
In fact, I'm pretty unsure about the whole multi-user side of this to be honest, as I've never done that before. Authentication for the above is handled by ssh, but there may well be subsequent permission issues to deal with, or similar, when the server and the clients are started by different users.
This approach should be possible with Windows/Cygwin as client and/or server, as Cygwin provides Emacs, OpenSSH, and X.org packages. (I regularly use Windows/Cygwin as a local display for Emacs running on Linux.) It may be harder to set up, though, and any permissions issues are probably different when you're using Cygwin.
I'm less sure how this would work without Cygwin. NTEmacs certainly won't talk to X.org, so I imagine you'd be terminal based in that instance. (There are probably other options, but Cygwin sounds to me like the best-integrated approach to using all of Emacs, SSH, and X on Windows).
Lastly, I imagine you're probably getting your "Connection refused" error because localhost is not running a sshd daemon? I would say that configuration of ssh is outside the scope of this question, but there are lots of resources online for that.
Depending on what you're trying to achieve, you may be able to use a combination of Emacs and Screen. By starting up Emacs from Screen on the remote machine and detaching from it, you can subsequently re-attach from a different machine that doesn't have Emacs. Again, whether this will work for you or not depends on what you're trying to do; however, for many Emacs use-cases, this can be very effective. If you're not familiar with using Screen in this manner, here is some reading material:
screen - The Terminal Multiplexer
I am not sure that would be possible. emacsclient uses tramp to connect to a remote server, and just by looking at the number of requires in the tramp elisp files (41) it seems very unlikely. You can try it yourself with the following:
zgrep -oE "\(require '[a-z-]+\)" *el.gz | sed -e 's%[a-z0-9-]\+\.el\.gz:%%g' | sort | uniq -cu | wc -l
I'm not an expert in emacsclient, but I don't think is was designed to do what you're looking for. I think the general use case is that emacsclient allows you to redirect new requests to open a file with emacs to a persistent emacs process to avoid what may be a bit of an overhead in startup time. You seem to be looking for more of a true client/server relationship.
I think to meet the goal you're aiming at you'll probably need to look a little outside emacs, probably a project unto itself - 'emacsRemoteClient. It boils down to one or two models; the file you want to edit would need to have it's path sent over to the server machine so that emacs could do some sort of remote tramp access & then spawn the xwindow locally (using the local X env or requiring an x server on windows)... or two, transferring the file to some temp location on the server box and again spawning the remote x window locally (followed by syncing the changes between the tmp & local file).
Would be cool to have something like that... but suspecting it'll involve a bit of work. Maybe we just need a version of emacs written in javascript and it can live in the cloud or on your browser... oh to have emacs keybindings in the browser ;-)
-Steve
I am having a conflict of ideas with a script I am working on. The conflict is I have to read a bunch of lines of code from a VMware file. As of now I just use SSH to probe every file for each virtual machine while the file stays on the server. The reason I am now thinking this is a problem is because I have 10 virtual machines and about 4 files that I probe for filepaths and such. This opens a new SSH channel every time I refer to the ssh object I have created using Net::OpenSSH. When all is said and done I have probably opened about 16-20 ssh objects. Would it just be easier in a lot of ways if I SCP'd the files over to the machine that needs to process them and then have most of the work done on the local side. The script I am making is a backup script for ESXi and it will end up storing the files anyway, the ones that I need to read from.
Any opinion would be most helpful.
If the VM's do the work locally, it's probably better in the long run.
In the short term, the ~equal amount of resources will be used, but if you were to migrate these instances to other hardware, then of course you'd see gains from the processing distribution.
Also from a maintenance perspective, it's probably more convenient for each VM to host the local process, since I'd imagine that if you need to tweak it for a specific box, it would make more sense to keep it there.
Aside from the scalability benefits, there isn't really any other pros/cons.