slowcp.c

// Build: gcc -std=c11 -Wall -Wextra slowcp.c -o slowcp

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

int main (int argc, const char *argv[])
{
    if (argc != 3) {
        printf ("Usage: %s <src> <dst>:\n"
                "   Copy contents of <src> to <dst>, with a max speed of 2 MiB per second.\n",
                argv[0]);
        exit (0);
    }

    FILE *outfile = fopen (argv[2], "w");
    FILE *infile = fopen (argv[1], "r");

    printf ("Copying %s to %s\n", argv[1], argv[2]);
    
    static char buf[1024*1024*2];
    int nread;
    do {
        nread = fread (buf, 1, sizeof (buf), infile);
        fwrite (buf, 1, nread, outfile);
        sleep (1);
        printf ("Copied %d bytes\n", nread);
    } while (nread == sizeof (buf));

    printf ("Copying done\n");

    fclose (infile);
    fclose (outfile);
}