This question already has answers here:
C++ system() function — How to collect the output of the issued command?
(8 answers)
Closed 8 years ago.
Showing snippet of c code.
char command[]="curl -X POST -d \'{\"device_id\": \"2204\"}' http://example.com/configure";
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system(command);
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Now this gives the output in terminal. I want to get this output in variable.. How should i acheive that ?
Pretty sure it's been answered here.
popen(3)
C++ system() function — How to collect the output of the issued command?
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This question already has answers here:
How can I print a string to the console at specific coordinates in C++?
(7 answers)
Closed 5 years ago.
Now, I can get a direction txt file from my code:
down
down
right
right
up
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I want to ask how can I display the walking process on linux terminal.
For instance, I want to use a dot representing a mouse which can execute the direction above.
nCurses is the best solution. You can het help with the built-in manual:
man -s 3 ncurses
A simpler way to do so is to use ANSI CSI escape sequences:
printf("\x1B[A"); // Up
printf("\x1B[B"); // Down
printf("\x1B[C"); // Left
printf("\x1B[D"); // Right
To move up and print a dot:
printf("\x1B[A.");
This question already has answers here:
Stop shell wildcard character expansion?
(4 answers)
Closed 6 years ago.
i'm trying to write code in C,which implements a simple calculator.
the input should come from the command line, so for example i if i run
./calculator 5 * 2
the result should be 10
the problem is that when i write * it shows all the files in the current directory and the program doesnt behave well.
there is anyway to overcome this problem?
i tried to find here or in other sites solutions,without success.
i need that * will Be interpreted as a char and not as a linux command.
thanks.
In linux shell, the * has special meaning. It is meant for globbing unless it is quoted like below
./calculator 5 '*' 2
You may also escape the asterisk to strip the special meaning from it
./calculator 5 \* 2
This question already has answers here:
How can I run an external program from C and parse its output?
(8 answers)
Closed 7 years ago.
I want to save the output from a bash script which is invoked from a C program to a variable declared in the C program. I searched and tried successfully calling a script using system, and I tried this, but it didn't work:
char* a;
system("a=`ls`");
printf("%s",a);
Use popen() system call. You can pass the cmd as the parameter. You will get the command output as text when the function returns. Hope this helps.
This question already has answers here:
How do I execute a command and get the output of the command within C++ using POSIX?
(12 answers)
How to run a bash script from C++ program
(5 answers)
Closed 8 years ago.
How might I go about writing a program in C that executes a .sh (shell script) file? I'm writing a program, and one of the functions requires running some shell scripts. Thanks!
Use the system function
system("myscript.sh");
This question already has answers here:
Problem redirecting a C program output in bash
(5 answers)
Closed 9 years ago.
So this is probably a stupid question, but I can't see what I'm doing wrong.
I am running a program that produces output when called like ./ar. The output looks like:
-0.00781 0.02344 0.98828
-0.01172 0.02734 0.98828
-0.01562 0.02344 0.98047
-0.00781 0.02344 1.00000
-0.00391 0.02344 0.98438
A new line of output is written every second.
When I call the code like this ./ar > log and kill the program using ctrl-c after a few seconds, the file log is empty.
I am running this code on an embedded system. The system has a writeable partition which is the partition that I am running in, and I have write access as I am logged in as root.
The reason is the lazy writing concept of UNIX system.
Are you sure you are looking at standard output in you call ./ar? It might be standard error.
So, try ./ar >log 2>err to have 2 files, one for stdout and one for stderr.
Or use ./ar 2>&1 >log to get one file for both streams.