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.
Reference/Source :
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
Debian APT