print a file date in a git-aware form (needed by pull.sh)

dateof.c

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <libgen.h>
#include <time.h>

main(argc, argv)
char **argv;
{
    struct stat st;
    struct tm time;
    char timestamp[80];
    char *pgm = basename(argv[0]);

    if ( argc < 2 ) {
	fprintf(stderr, "usage: %s file\n", pgm);
	exit(1);
    }
    if ( stat(argv[1], &st) == -1 ) {
	perror(argv[1]);
	exit(1);
    }
    
    /* 2005-04-07T22:13:13 */

    strftime(timestamp, sizeof timestamp, "%Y-%m-%d %H:%M:%S", gmtime(&st.st_mtime));
    puts(timestamp);
    exit(0);
}