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

// Grab the file extension of the filename passed.
// TODO: current just does it until the first. Add in variations to grab all,
// only specific entries like .tar.gz, etc.

void usage(void)
{
    printf("fex: returns the extension of the filename passed\n");
    exit(0);
}

int main(int argc, char **argv) 
{
    if (argc <= 1)
	usage();

    const char *file = argv[1]; // FIXME: unsafe.
    size_t len = strlen(file);
    if (len == 0)
	fprintf(stderr, "length of file cannot be zero\n"), exit(-1);

    for (len--; len != 0; len--)
    {
	if (file[len] == '.')
	{
	    printf("%s\n", file + len + 1);
	    return 0;
	}
    }
    return 0;
}