Display version information and exit.
.TP
.BI \-\-terse\-version \fR=\fPversion
-Set terse version output format (Current version 3, or older version 2).
+Set terse version output format (default 3, or 2 or 4)
.TP
.B \-\-help
Display usage information and exit.
Default: true.
.TP
.BI offset \fR=\fPint
-Offset in the file to start I/O. Data before the offset will not be touched.
+Start I/O at the provided offset in the file, given as either a fixed size or a
+percentage. If a percentage is given, the next \fBblockalign\fR-ed offset will
+be used. Data before the given offset will not be touched. This effectively
+caps the file size at (real_size - offset). Can be combined with \fBsize\fR to
+constrain the start and end range of the I/O workload.
.TP
.BI offset_increment \fR=\fPint
If this is provided, then the real offset becomes the