How to keep writing the results of system("ping 10.50.132.10 -t"); in a text file using C++?
A way is to do directly with shell command:
system("ping 10.50.132.10 -t >> file.txt");
After your operations, you can read from "file.txt"!
There are a couple solutions to this. The first and simplest would be to simple add a redirect in the system call:
system("ping 10.50.132.10 -t > some_file.txt");
Another and more advanced way would be to read the output into your program, and write it out to file yourself. For this look either at _popen or CreateProcess.
Related
I’m looking for a C/C++ way to execute a shell command and store the output of that command in a std::string or file, without the output being automatically printed to the console.
All approaches I’ve seen can do exactly that, but also print the execution result to the console.
For example with a combination of
FILE* pipe = popen("ls", "r");
and
fgets()
I’m able to do just that, but with the printing to the console.
Is there perhaps a way to redirect the stream’s buffer from std::cout to std::sstream, or has it semething to do with Ubuntu?
Any help is appreciated :)
The 2>&1 part from the comments did it.
I intend to run a c++ program on spark using rdd.pipe() operator in order to see the possible benefits of the program running in parallel.
In terminal i run it like this:
./program program_mode -t input -i output
In spark driver i've attempted:
mapDataset.pipe(s"/path/to/program program_mode -t $mapDataset -i /path/to/output"
where mapDataset is the input rdd (type .fasta file) that i have successfully loaded in spark driver,but this doesnt work.
The general problem is that the program expects to have its input through the flags but in spark the input is in the rdd that i've created on which pipe is called.
Any idea on how i can implement this communication correctly?
If your program uses streams, then change the way it behaves.
Instead of opening an ifstream for a file when it's on the command line, pass in stdin to your functions. Same for the output stream.
I have a c++ program that run a command and pass some arguments to it. The code is as follow:
int RunApplication(fs::path applicationPathName,std::string arguments)
{
std::string applicationShortPath=GetShortFileName(applicationPathName);
std::string cmd="\""+applicationShortPath +"\" "+ arguments+" >>log.txt 2>&1 \"";
std::cout<<cmd<<std::endl;
int result=std::system(cmd.c_str());
return result;
}
When I run system command, the cmd window appears shortly and then closes, but the result is 1 and the cmd was not run (the command should generate output which is not generated).
To check that the cmd is correct, I stopped the application just before system line and copy/ paste cmd content to a cmd window and it worked.
I am wondering how can I find why application is not run in system()?
the cmd has this value just before running it:
"D:/DEVELO~3/x64/Debug/enfuse.exe" -w --hard-mask --exposure-weight=1 --saturation-weight=0.328 --contrast-weight=0.164 -o "C:/Users/m/AppData/Local/Temp/1.tif" "C:/Users/m/AppData/Local/Temp/1.jpg" "C:/Users/m/AppData/Local/Temp/2.jpg" >>log.txt 2>&1 "
How can I find why it is not working?
Is there any way that I set the system so it doesn't close cmd window so I can inspect it?
is there any better way to run a command on OS?
Does Boost has any solution for this?
Edit
After running it with cmd /k, I get this error message:
The input line is too long.
How can I fix it other than reducing cmd line?
There are two different things here: if you have to start a suprocess, "system" is not the best way of doing it (better to use the proper API, like CreateProcess, or a multiplatform wrapper, but avoid to go through the command interpreter, to avoid to open to potential malware injection).
But in this case system() is probably the right way to go since you in fact need the command interpreter (you cannot manage things like >>log.txt 2>&1 with only a process creation.)
The problem looks like a failure in the called program: may be the path is not correct or some of the files it has to work with are not existent or accessible with appropriate-permission and so on.
One of the firt thing to do: open a command prompt and paste the string you posted, in there. Does it run? Does it say something about any error?
Another thing to check is how escape sequence are used in C++ literals: to get a '\', you need '\\' since the first is the escape for the second (like \n, or \t etc.). Although it seems not the case, here, it is one of the most common mistakes.
Use cmd /k to keep the terminal: http://ss64.com/nt/cmd.html
Or just spawn cmd.exe instead and inspect the environment, permissions, etc. You can manually paste that command to see whether it would work from that shell. If it does, you know that paths, permssions and environment are ok, so you have some other issue on your hands (argument escaping, character encoding issues)
Check here How to execute a command and get output of command within C++ using POSIX?
Boost.Process is not official yet http://www.highscore.de/boost/process/
What I'd like to do is have my C++ code open up Mplus (statistical program that I've downloaded on my computer) and run it. Is it possible?
You may be able to do what you want with std::system() calls like:
std::system("program -e input_commands.txt"); // Assuming it accepts some sort of command line args
std::system("program < input_commands.txt"); // Assuming it responds to stdin
It depends on the program if this approach will work.
I am using int res = system("uname -p"); in my c++ code.
It will give the the result in standard output by using
fprintf(stdout,"execution returned %d.\n",res);
I want to store this result string in a variable, I am unable to store it.
I google it but unable to find proper solution, Can any one tell me the correct way.
First, you don't need to run the uname command programmatically to get your processor. You can simply run the uname(2) syscall (which the uname command invokes). And you could also read and parse /proc/cpuinfo from your program.
If you wanted to read the output of some command, use popen(3) library function.
See also my answer to a related question.