SSH 用于运行远程二进制档

Question

I am configuring a vs-code extension to send a cross-compiled binary to a raspberry pi.

Every step from compiling to copying the file runs fine.

ssh pi@123.123.123.123 "sudo mkdir /home/pi/remotePi/"; 
ssh pi@123.123.123.123 "sudo rm /home/pi/remotePi/blink_example";
ssh pi@123.123.123.123 "sudo chown pi /home/pi/remotePi/"; 
scp -l 8192 build/blink_example pi@123.123.123.123:/home/pi/remotePi/ && 
ssh pi@123.123.123.123 "echo "scp complete"" && 
ssh pi@123.123.123.123 "/home/pi/remotePi/blink_example"

Output:

mkdir: cannot create directory ‘/home/pi/remotePi/’: File exists
blink_example                                                                                                                     100% 8692   277.3KB/s   00:00    
scp complete

But when I try to run the file through an SSH command, the command stalls.

ssh pi@123.123.123.123 "home/pi/remotePi/blink_example"

It will eventually run, but it can take around 10 minutes. If I ssh into the pi and run the binary through an actual terminal, it runs immediately.

I have noticed that when it finally runs (using my extension), there are a lot of print statements (the test code just prints the read value from a pin). Does that mean it is running, but I'm maybe not getting the prints until there is enough to fill a packet?

So my question is, how can I run a binary on a remote machine and receive the terminal output in a timely manner?

---

Edit

I modified my program to not have any delays between print statements (essentially spamming stdout). This resulted in the ssh command ssh pi@123.123.123.123 "/home/pi/remotePi/blink_example" to return immediately and with all the prints.

This leads me to believe that there is a buffer that I need to fill (or limit the size of) before any terminal information is returned to the local device from the remote.

Answer 1

I figured out a solution, but it doesn't answer any of the questions about why spamming stdout will cause ssh to give a terminal output sooner.

In the original blink_example, I was using printf("pin 17: %d\n", digitalRead(17)); for displaying the value.

I converted the test application to c++ (not a terribly difficult task) and used std::cout << "pin 17: " << digitalRead(17) << std::endl; . Using this caused the terminal to give feedback right away.