if (opts->argc size = sb.st_size;
stat, fstat, lstat - get file status
stat() stats the file pointed to by path and fills in buf.
fstat() is identical to stat(), except that the file to be
stat-ed is specified by the file descriptor fd.
Linux Programmer's Manual.
pv (Pipe Viewer) can be inserted into any normal
pipeline between two processes to give a visual
indication of how quickly data is passing through,
how long it has taken, how near to completion it
is, and an estimate of how long it will be until