Progress Pipe: Read a block of data from stdin, write it to stdout. Activity is indicated by a '.' to stderr.

pipe_progress.c

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

#define PIPE_PROGRESS_SIZE 4096

/* Read a block of data from stdin, write it to stdout.
 * Activity is indicated by a '.' to stderr
 */
int main(int argc, char **argv)
{
	char buf[PIPE_PROGRESS_SIZE];
	time_t t = time(NULL);
	size_t len;

	while ((len = fread(buf, 1, PIPE_PROGRESS_SIZE, stdin)) > 0) {
		time_t new_time = time(NULL);
		if (new_time != t) {
			t = new_time;
			fputc('.', stderr);
		}
		fwrite(buf, 1, len, stdout);
	}

	fputc('\n', stderr);

	return 0;
}