Access a machine remotely on the same network - bash

I am trying to write a program (not bash scripting) that accesses another machine remotely on the same network to run commands on its terminal. How can I go about doing that? Any help would be appreciated.

You can do this on a case by case basis using ssh and if you are trying to execute commands on a number of machines simultaneously, look at an orchestration tool such as Ansible.

Related

Possible ways to run windows batch command from Unix

I am trying to run a windows batch command from CentOS 6. I would like to know the best way to achieve this. I explored PsExec and WinExe utilities in unix to connect to windows machine and run the required commands.
I am trying this on a windows VM which is within company network, hence kindly highlight any specific network issues that I may have to check for the setup to run.
Any pointers would help.
Have you seen the examples from the PowerShell for Linux GitHub pages, as the working examples seem to cover this off nicely?
https://github.com/PowerShell/PowerShell/tree/master/demos/SSHRemoting
It will require SSH installed onto your Windows server, but otherwise seems to tick all of your boxes.

Running awk script on local and remote files?

I have an awk script that runs on specific log files. Initially we ran this on the machine that generates the log files so all was good, I just basically at the end of the script pointed to the local directory and file I need it to run on, for example: /logs/logfile1
But now, I've added several other machines to help load balance our application, so each time a particular machine is accessed (in round robin fashion) that machine writes its own log file local to that machine.
How do I get the script to run on one machine but access the log files from all of the other machines as well? (I could copy the script and run locally on each of the machines and append the outputs to one file as there are only 5 machines right now, but I figure there is an easier solution).
Also I run CentOS 6.x on these servers if that is helpful
EDIT: I suppose I could create soft links to the other machines, on the machine that is running the script. Just wondering if there is something easier?
Mount the other machines file systems (via ssh, nfs, etc.) on the machine with the script.
Mounting the required directories of all machines on one machine is probably the best solution. However, if you expect the number of machines to increase to a larger number in future, you should try for a scalable solution.
You could have a solution as below:
Maintain a file in one machine with a list of all other machines and their respective directories.
Have a script to telnet/ssh to each of those remote machines and execute your awk script.
Retrieve all the output files via ftp tom one machine and merge.

Is it possible to run a batch script remotely on a Windows machine from Linux without installing ssh?

I am looking for a way in Linux to run a batch script on a remote Windows machine. I already searched some forums and the Internet and found e.g. this question.
It seems that the easiest way so far is using ssh. But do Linux or Windows also offer some built-in tools to solve this problem (something like at-command for Linux-to-Windows)?
Have a look at this. It seems to be the linux counter part to the Windows Sysinternals PsExec tool.
.
Another option is to use ad-hoc services for remote execution, e.g. Nagios NRPE for windows. It is not exactly what the developers had in mind, but it can be (ab)used in this way.

How to spawn Linux process from Windows application?

My interactive 32-bit Windows app (now moving from Delphi [Ent] 2007 to 2009) uses command-line interactions to spawn child processes that do computationally-intensive tasks, which in turn write text files that the GUI parent app parses and analyzes - resulting in an interactive graphical display of the results.
I have access to a multiprocessor (multi-user) Linux cluster (via ssh), and would like to off-load the heavy lifting to that cluster. My question is how to spawn the processes in Linux from my Windows app. I can envision using secure FTP to put and get files, but not sure how to spawn the child processes in Linux.
Some leads for further reading would be fine - but code/pseudocode would be ideal. I can imagine that this may be more about Windows-Linux interaction than Delphi.
if you have access to ssh, one option is to issue commands through that.
For example:
ssh user#host ls -l ~
will in the ssh terminal show the files in the user's home directory. I'm not sure if this is what you really want. But it would likely work.
If you do this, you almost certainly want to setup SSH password less logins
However, A more ideal solution would likely be to setup a daemon on the linux boxes whose sole job is to run specific long running tasks in the background and let you fetch the results later.
You're going to have to install something on the Linux machine to run the process. You might find some kind of clustering or batch job submission API you can install and access from Windows. You might have to code a custom server. You might be able to run everything over ssh if you can drive an ssh process from Windows and if you have sshd installed on the Linux side. But my preference would be to write a webservice or simple CGI script on the Linux side designed to take your arguments and data and return the result over plain old http (or https as the case might be).
One way or another, this is going to encompass more than just coding on the Windows side.
I would download the full "putty" package.
As well as the excellent secure shell terminal, it includes PSCP to transfer files securely and PLINK to remote execute commands over SSH.
Hint: you will need to set up the full public/private key configuration for PLINK to work without an annoying password prompt. There is a useful guide http://unixwiz.net/techtips/putty-openssh.html>here.

psexec inside visual studio

I've been trying to get psexec to run executables on remote machines from custom build tasks in visual studio. All of these commands work from the command line but running it from an application seems to be a problem. Some commands work, on other psexec hangs and consequently so do msbuild and visual studio 2005. I'm calling SharePoint's stsadm.exe in this case, but this problem occurs with a lot of programs, when running psexec from an application. There are lots of people having this problem, but there seems to be no solution, so my question is: Does anyone know a working alternative to psexec?
I've experienced 'hangs' when executing PSEXEC against a remote system, but I always attributed it to the security context in which the remote process was running under.
From PSEXEC help:
If you omit a username the remote
process runs in the same account from
which you execute PsExec, but because
the remote process is impersonating it
will not have access to network
resources on the remote system. When
you specify a username the remote
process executes in the account
specified, and will have access to any
network resources the account has
access to. Note that the password is
transmitted in clear text to the
remote system.
If your executing a process remotely, that then needs to access the database (stsadm.exe), then it could be failing trying to access the network resource, depending on how PSEXEC was executed. If thats the case, I'd imagine it would eventually time out and give some sort of resource unavailable message.
There are two things that generally done when executing deployment steps against a remote machine to prevent the behavior your describing:
Like rifferte mentioned, make sure all assets needed to
deploy are local to the remote
machine (copy files, etc) before
using PSEXEC to execute the script (*.bat, *.vbs, *.ps, etc) -
so that everything runs 'local' to
the remote machine.
Run PSEXEC using
a domain username/password when
executing it - note that this
information is passed in clear text
to the remote server.
There's always RCE.
RemCom is a small (10KB upx packed)
remoteshell / telnet replacement that
lets you execute processes on remote
windows systems, copy files on remote
systems, process there output and
stream it back. It allows execution of
remote shell commands directly with
full interactive console without
having to install any client software.
On local machines it is also able to
impersonate so can be used as a silent
replacement for Runas command.
You can try to have psexec call a bat program that executes what you need on the remote machine. I ran into this issue with installutil.exe. A simple bat file on the remote machine resolved it.
You should also share your experience on the sysinternals board. There may be something they can do in a future revision.

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