open telnet using shell and passing commands

Question

I am new to linux and shell scripting. I want to connect to localhost and interact it.

 #! /bin/bash
 (exec /opt/scripts/run_server.sh)

when i execute this bash script, it starts listening on a port.

Listening on port xxxxx

Now i want to issue this command "telnet localhost xxxxx" I tried something like this:

#! /bin/bash
(exec /opt/opencog/scripts/run_server.sh)&&
telnet localhost xxxxx

It is still listening on the port. But i think second command is not running. I expect another window showing that it is being connected like this.

vishnu@xps15:~$ telnet localhost xxxx
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
server> 

The reason why i executing these as a script is that, automatically in the server i need to carry out some process by issuing certain commands like this "scm" "parse" etc.....

vishnu@xps15:~$ telnet localhost xxxx
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
server>scm
Entering scheme shell; use ^D or a single . on a line by itself to exit.
guile> (parse "i eat apple")

I have lots of text coming. Manually i cant issue this parse command for each and every sentence. so i want to automate. So i need to write a script for connecting to the server and interacting.

Any guidelines. Finally How to interact/send commands to this guile shell?

Answer 1

One way to login to the linux server as a same or different user and run some command or .sh script (very useful for post-commit hooks or cron jobs) is to use program called sshpass, for example a cron job command or svn post-commit hook would look like this:

/usr/bin/sshpass -p 'password' /usr/bin/ssh 
-o StrictHostKeyChecking=no  -q user@localhost 'any command'

Just replace password with your password, and user with your user, and put command that you need to run as that particular user...

To install sshpass it on ubuntu just type

apt-get install sshpass

Or on CentOs

yum install sshpass

Answer 2

I solved this with the netcat (nc) command.

  $ echo "command1\ncommand2\n" | nc localhost xxxxx

I could manually connect to localhost using telnet localhost xxxx and then i can pass commands from shell to localhost like this.

Answer 3

If you need to use telnet, this solution may help you. Otherwise, use ssh, as other answer suggests.

You can use anything that produces output to write lines one by one, followed by "\r\n", and pipe these lines to ncat, e.g.:

echo -e "command1\r\ncommand2\r\n" | ncat localhost 5000

-e option makes echo interpret "\r\n" as special symbols.

Answer 4

Newer Answer

I found and tested in shorter toggle mechanism.

The configuration for Windows Feature:

• Windows Subsystem for Linux is installed.
• Windows Hypervisor Platform is installed.
• Hyper-V is installed.

If you need the Emulator, you only need to turn off Hypervisor + Restart. Run: bcdedit /set hypervisorlaunchtype off

If you need the Docker back, you can run the hypervisor hence disabling Emulator. Run: bcdedit /set hypervisorlaunchtype auto

You need to restart after setting Hypervisor

You cannot run both at the same time. Another forum worth checking in How about running docker? in my older answer below.

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Older Answer

I think I solved this issue, tested to run from CMD / Android Studio and ran perfectly as before installing WSL. There are several step we go:

---

Configuring Windows Feature:

1. Removed Windows Subsystem for Linux
2. Removed Windows Hypervisor Platform
3. Removed Hyper-V

Here is my current setup:

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Reverting AVD setup

I know after removing there are some odds because the AVD still get the same error as before and expected to get into WSL. I stumbled and found something when ran:

C:\Users\[NAME]\AppData\Local\Android\Sdk\emulator\emulator-check.exe accel

That command will check the current accel. It explains that the Hypervisor need to be set off and give specific help: run bcdedit /set hypervisorlaunchtype off.

After running the bcdedit, I restarted and all is reverted. Now I can run emulator both from CMD and Android Studio perfectly.

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How about running docker?

Sad truth, yeah you cannot run both pararel. There are several workaround in this forum:

How can I run both Docker and Android Studio Emulator on Windows?

Several option ranging from changing emulator, add & remove docker when in need using above step, created nested vm, etc. My personal choice right now is using another Emulator for the time being and removed docker for the latter.

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Answer 5

This issue is tracked by Google bug https://issuetracker.google.com/issues/202188690

Answer 6

This problem only occurs with AMD processors, I have two systems both with WSL2 and Docker running on the latest Windows 11 (Insider Beta) build. One with an AMD Ryzen 5950 and one with an Intel i7-8086K. On the Intel system the emulator runs fine with hardware acceleration together with WSL2 and Docker.

On the AMD I run into the same error when running the emulator with hardware acceleration. In the Windows 10 Insider builds before Windows 11 it still worked.

A very similar problem was introduced before in Windows 10 build 10.0.21292 and later fixed in build 21327. (https://github.com/microsoft/WSL/issues/6471) But this problem affected both Intel and AMD.

I haven't tried to turn off the AMD fTPM yet, as this is the only other change apart from updating Windows 10 Insider (dev ring) to Windows 11.

The Android Emulator Hypervisor Driver for AMD processors only works when the Windows Hypervisor is disabled, it's not used for WHPX.

The Windows Feedback is full of reports of this problem, please upvote them.

Answer 7

Android Studio emulator doesn't support run Hyper-V on Windows 11, we can disable Hyper-V to run but if we do that applications which require Hyper-V to run like WSL2, Docker then fail to run.

While waiting Google update Android Studio emulator support Hyper-V we have a workaround solution to run both by using another emulator which support Hyper-V like Bluestack 5 version "Nougat 64 bit (Supports Hyper-V)" at the link below https://www.bluestacks.com/download.html