mkfs supports the option -V/--version.
Add its description to print_usage().
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
fprintf(stderr, "\t -s --sectorsize min block allocation\n");
fprintf(stderr, "\t -r --rootdir the source directory\n");
fprintf(stderr, "\t -K --nodiscard do not perform whole device TRIM\n");
+ fprintf(stderr, "\t -V --version print the mkfs.btrfs version and exit\n");
fprintf(stderr, "%s\n", BTRFS_BUILD_VERSION);
exit(1);
}