I have developed a c++ app that runs on debian jessie server. Since I'm quite new in linux distros and specially the server ones that provide only terminal, I 'd like to find out if there is a way to watch the %CPU and %MEM on the same time that the c++ app runs. I tried to run
./C++_APP & ps -aux | grep .C++_APP
but ps ran only at the beginning. Is this possible somehow either with ps or with another command?
Use watch. You can pass your ps (along with its arguments) to it. If you don't run your application as a background process you will have to use a second terminal session or pipe the results to a file that you can look at later on.
You can use/install htop.
Set filter to match your executable name.
You may try that:
./C++_APP & wait && PID=`pidof -s -x C++_APP` && top -b -p $PID
It will display stats every second.
To break CTRL+C
To kill your app type than
kill $PID
Related
I have the newest (2020.3 EAP ATM) version of CLion and I currently use it to remote debug a program on an embedded target (linux-mipsel).
Everything works as expected, after a bit of configuration, using self-built cross-toolchain and gdbserver.
My only problem is hitting the "red square" to stop execution will neither kill the running program nor gdbserver itself.
This means next iteration of edit-compile-debug cycle I will have two copies of both (I can get more, if I insist) which will not work as each tries to open the same resources (e.g.: a serial port) concurrently.
I have to manually log into target and kill the offending processes.
Am I missing something, is it a known bug or what?
Small update:
gdbserver is actually killed (does not show in ps ax) but underlying program (debugee) is still there. I am unsure why I was convinced otherwise, my bad.
This is a known issue and will hopefully be fixed soon.
Here is the link to the youtrack issue: https://youtrack.jetbrains.com/issue/CPP-20346
You could try the suggested workarounds:
Add pre-deploy configuration which kills running instances of the program
Follow the instructions for the gdb configuration in the comments:
GDB Server: /bin/bash
GDB Server args: -c "gdbserver :1234 /home/pi/myapp; pkill -e myapp"
The second config did not work for me, so I added the execution of an external tool where I run in /bin/bash the command -c "pkill -e myapp || true". The true is mandatory to avoid errors if the program is not running.
I want to write a program that can capture the input/output of a pseudo terminal without it affecting the original terminal. It can be likened to pointing script to a /dev/pts/<n>.
Use Case: A user ssh's into my machine and runs an interactive tool. With audit, I can see commands running but I need to see the output also. I can listen in on /dev/pts/<n> but then the original logged in user does not get the output.
I want to write my own program to handle this case. Is this problem actually solvable and if so, where should I be looking to find a solution?
That's solvable by using ptrace(2) on the ssh server process which handles to master end of the pseudo-terminal (which is usually the parent process of the shell running in the terminal).
You can start with strace which is itself using ptrace(2), e.g.
strace -p <pid> -e trace=read,write \
-e read=<fds opened to /dev/ptmx> \
-e write=<fds opened to /dev/ptmx>
This will show you everything that's read or written to that pseudo-terminal. You can get the "fds opened to /dev/ptmx" from ls -l /proc/<pid>/fd.
You can then look at what strace is doing -- e.g. by stracing strace itself with
strace -e trace=ptrace,process_vm_readv strace ...
and by studying its source code.
You can of course modify the ssh server itself to log all that info, or just tweak its config options (e.g. LogLevel -- which can be modified on a per-user or connecting host basis).
This is script content, located in /etc/init.d/myserviced:
#!/lib/init/init-d-script
DAEMON="/usr/local/bin/myprogram.py"
NAME="myserviced"
DESC="The description of my service"
When I start the service (either by calling it directly or by calling sudo service myserviced start), I can see program myprogram.py run, but it did not return to command prompt.
I guess there must be something that I misunderstood, so what is it?
The system is Debian, running on a Raspberry Pi.
After more works, I finally solved this issue. There are 2 major reasons:
init-d-script actually calls start-stop-daemon, who don't work well with scripts specified via --exec option. When killing scripts, you should only specify --name option. However, as init-d-script always fill --exec option, it cannot be used with script daemons. I have to write the sysv script by myself.
start-stop-daemon won't magically daemonize the thing you provide. So the executable provided to start-stop-daemon should be daemonized itself, but not a regular program.
I am writing a program that logs into another system via SSH using the libssh2 library. Once logged in, I execute a command using:
libssh2_channel_exec(sshchannel, command)
The command executes okay. However, once I close the channel the process running is killed. In my case, the command (executing a binary executable) will run for a long period of time and my program cannot wait for it to terminate. I've tried issuing the following commands all to the same result (the process is still killed upon closing the channel):
/path/myprog
nohup /path/myprog
nohup /path/myprog &
/path/myprog &; disown
Further, I've observed this behavior for both libssh and libssh2. Is there some option or command I am missing?
Thanks in advance.
you can use the unix at command:
echo "cmd" | at now
In order to choose between what type of app indicators to use for a program, I need to detect whether I'm in a Unity desktop or not. Is this possible? Is it possible when I don't have access to the environment?
It looks like there's also XDG_CURRENT_DESKTOP:
rubiojr#rubiojr-VirtualBox:~$ echo $XDG_CURRENT_DESKTOP
Unity
See https://askubuntu.com/questions/70296/is-there-an-environment-variable-that-is-set-for-unity
In Ubuntu you can use following commands:
echo $DESKTOP_SESSION: This command return ubuntu when you are using Unity and ubuntu-2d when you are using Unity 2D and ...
sudo grep "Starting session" /var/log/lightdm/lightdm.log: Because of last version of Ubuntu use lightdm as display manager you can see last line of the lightdm.log file.
Just shell execute ps aux | grep unity, this is cross-plattform for linux. Even works on ARM cores.
On my 11.04 Ubuntu running unity it returns unity-2d-panel, unity-2d-launcher and more processes. Can't confirm if this is true on every linux platform.
Look in the list of environment variables for unity by running this command line:
env | grep -i unity
If as in this answer you see XDG_CURRENT_DESKTOP=Unity then you know it is in use. Alternatively, you could of course check for desktop rather than unity.