Getting output of a system command from stdout in C

Question

I'm writing a C program under Android/Linux that runs a system command. The command outputs some text to stdout, and I'm trying to capture the output into a string or character array.

For example:

system("ls");

would list the contents of the current directory to stdout, and I would like to be able to capture that data into a variable programmatically in C.

How do I do this?

Thanks.

jxh · Accepted Answer · 2012-08-07 07:06:03Z

20

You want to use popen. It returns a stream, like fopen. However, you need to close the stream with pclose. This is because pclose takes care of cleaning up the resources associated with launching the child process.

FILE *ls = popen("ls", "r");
char buf[256];
while (fgets(buf, sizeof(buf), ls) != 0) {
    /*...*/
}
pclose(ls);

answered Aug 7, 2012 at 7:06

jxh

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2 Comments

Shashank Singh Over a year ago

This only gets the output stream, ho to get the error stream too?

jxh Over a year ago

@ShashankSingh tio.run/…

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