Teach dd(1) about parity bits.

1 files changed, 20 insertions, 0 deletions

diff --git a/bin/dd/dd.1 b/bin/dd/dd.1
index 588b62f..31150fd 100644
--- a/bin/dd/dd.1
+++ b/bin/dd/dd.1
@@ -231,6 +231,13 @@ and
 systems.
 .It Cm lcase
 Transform uppercase characters into lowercase characters.
+.It Cm pareven , parnone , parodd , parset
+Output data with the specified parity.
+The parity bit on input is stripped unless
+.Tn EBCDIC
+to
+.Tn ASCII
+conversions is also specified.
 .It Cm noerror
 Do not stop processing on an input error.
 When an input error occurs, a diagnostic message followed by the current
@@ -355,6 +362,19 @@ be written to the standard error output
 in the same format as the standard completion message and
 .Nm
 will exit.
+.Sh EXAMPLES
+Check that a disk drive contains no bad blocks:
+.Dl dd if=/dev/ad0 of=/dev/null bs=1m
+.Pp
+Do a refresh of a disk drive, in order to prevent presently
+recoverable read errors from progressing into unrecoverable read errors:
+.Dl dd if=/dev/ad0 of=/dev/ad0 bs=1m
+.Pp
+Remove parity bit from a file
+.Dl dd if=file conv=parnone of=file.txt
+.Pp
+Check for (even) parity errors on a file:
+.Dl dd if=file conv=pareven | cmp -x - file
 .Sh DIAGNOSTICS
 .Ex -std
 .Sh SEE ALSO