How to execute a shell script from C in Linux?

How can I execute a shell script from C in Linux?

You can use `system`:

system("/usr/local/bin/foo.sh");

This will block while executing it using `sh -c`, then return the status code.

If you need more fine-grade control, you can also go the `fork` `pipe` `exec` route. This will allow your application to retrieve the data outputted from the shell script.

I prefer fork + execlp for "more fine-grade" control as doron mentioned.
Example code shown below.

Store you command in a char array parameters, and malloc space for the result.


int fd[2];
pipe(fd);
if ( (childpid = fork() ) == -1){
fprintf(stderr, "FORK failed");
return 1;
} else if( childpid == 0) {
close(1);
dup2(fd[1], 1);
close(fd[0]);
execlp("/bin/sh","/bin/sh","-c",parameters,NULL);
}
wait(NULL);
read(fd[0], result, RESULT_SIZE);
printf("%s\n",result);

If you're ok with POSIX, you can also use [`popen()`](

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[`pclose()`](

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)

#include <stdio.h>
#include <stdlib.h>

int main(void) {
/* ls -al | grep '^d' */
FILE *pp;
pp = popen("ls -al", "r");
if (pp != NULL) {
while (1) {
char *line;
char buf[1000];
line = fgets(buf, sizeof buf, pp);
if (line == NULL) break;
if (line[0] == 'd') printf("%s", line); /* line includes '\n' */
}
pclose(pp);
}
return 0;
}

A simple way is.....


#include <stdio.h>
#include <stdlib.h>


#define SHELLSCRIPT "\
#/bin/bash \n\
echo \"hello\" \n\
echo \"how are you\" \n\
echo \"today\" \n\
"
/*Also you can write using char array without using MACRO*/
/*You can do split it with many strings finally concatenate
and send to the system(concatenated_string); */

int main()
{
puts("Will execute sh with the following script :");
puts(SHELLSCRIPT);
puts("Starting now:");
system(SHELLSCRIPT); //it will run the script inside the c code.
return 0;
}

Say thanks to
Yoda @<http://www.unix.com/programming/216190-putting-bash-script-c-program.html>