execute bash commands in a c file and store the output in an array

Question

I'm trying to store the number of page faults into an array in my c program. I want to execute bash command and store the output of it in an array. here's my command

$ cat /proc/vmstat | grep pgfault

Include that line in your C program that creates an array and then prepares to store the data within a loop. — Juniar
– Juniar, Commented Sep 10, 2014 at 22:36

John Hascall · Accepted Answer · 2018-08-06 21:19:25Z

1

A simple start, can be embellished and improved...

char * lines[2000];         /* 2000 lines enough? */
int    n = 0;

FILE * fp = popen("your command here", "r");
if (fp == NULL) abort();

lines[0] = malloc(1000);    /* 1000 byte lines enough? */
while ((fgets(lines[n], 1000, fp) != NULL) {
    if (n == 1999) abort();       /* oh crud... */
    lines[++n] = malloc(1000);
}
free(lines[n]);
pclose(fp);
/* do something with lines[0 .. n-1] here */
/* then free them */

edited Aug 6, 2018 at 21:19

answered Sep 10, 2014 at 20:51

John Hascall

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1 Comment

michaelmeyer Over a year ago

It sure can be embellished, perhaps by avoiding leaking 1999 lines (in the worst case).

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