.I hash
function, which can be any hash function supported by Python's
.BR hashlib .
-If this option may be omitted then the hash is read from the cache file;
-if there is no cache file either, then an error is reported.
+This option may be omitted: if it is, then the hash is read from the
+cache file; if there is no cache file either, then an error is reported.
.TP
.B \-u, \-\-udiff
Rather than produce a manifest, read a unified
.BR symbolic-link .
The name is followed by
.RB ` \~\->\~ '
-and the link target (or by
+and the link target (or
.BI <E nn \~ message >
if there was an error reading the link destination).
.TP