How to run 2 commands on bash concurrently

Question

I want to test my server program,(let's call it A) i just made. So when A get executed by this command

$VALGRIND ./test/server_tests 2 >>./test/test.log

,it is blocked to listen for connection.After that, i want to connect to the server in A using

nc 127.0.0.1 1234 < ./test/server_file.txt

so A can be unblocked and continue. The problem is i have to manually type these commands in two different terminals, since both of them block. I have not figured out a way to automated this in a single shell script. Any help would be appreciated.

Does this answer your question? Can I run two bash commands at once and send only one to the background? — oguz ismail
– oguz ismail, Commented Dec 1, 2019 at 13:22
I don't think so, but the background symbols & worked for me. — Van Teo Le
– Van Teo Le, Commented Dec 1, 2019 at 13:41

Rohan Talesara · Accepted Answer · 2019-12-01 13:37:34Z

1

You can use & to run the process in the background and continue using the same shell.

$VALGRIND ./test/server_tests 2 >>./test/test.log &
nc 127.0.0.1 1234 < ./test/server_file.txt

If you want the server to continue running even after you close the terminal, you can use nohup:

nohup $VALGRIND ./test/server_tests 2 >>./test/test.log &
nc 127.0.0.1 1234 < ./test/server_file.txt

For further reference: https://www.computerhope.com/unix/unohup.htm

answered Dec 1, 2019 at 13:37

Rohan Talesara

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dash-o · Accepted Answer · 2019-12-01 13:45:35Z

1

From the question, it looks if the goal is to build a test script for the server, that will also capture memory check.

For the specific case of building a test script, it make sense to extend the referenced question in the comment, and add some commands to make it unlikely for the test script to hang. The script will cap the time for executing the client, executing the server, and if the test complete ahead of the time, it will attempt to shutdown the server.

   # Put the server to the background
(timeout 15 $VALGRIND ./test/server_tests 2 >>./test/test.log0 &
svc_pid=$!

   # run the test cilent
timeout 5 nc 127.0.0.1 1234 < ./test/server_file.txt
   .. Additional tests here

   # Terminate the server, if still running. May use other commands/signals, based on server.
kill -0 $svc_id && kill $svc_pid
wait $svc_pid

   # Check log file for error
   ...

answered Dec 1, 2019 at 13:45

dash-o

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2 Comments

Van Teo Le Over a year ago

if i specify close(fd) in my code, then would kill be unnecessary?

dash-o Over a year ago

You will have to provide more details on how the code works, and where will the close be issue. But in general, a server side close will NOT guarantee that the server will terminate, unless the server is designed to terminate after one request (or a designated shutdown request).

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