Add a "fillchar" command line argument to dd(1) that permits the user

to specify an alternative padding character when using a conversion
mode, or when using noerror with sync and an input error occurs.  This
facilities reading old and error-prone media by allowing the user to
more effectively mark error blocks in the output stream.

1 files changed, 11 insertions, 0 deletions

diff --git a/bin/dd/dd.1 b/bin/dd/dd.1
index 1cbe499..6f3298e 100644
--- a/bin/dd/dd.1
+++ b/bin/dd/dd.1
@@ -84,6 +84,13 @@ Copy
 .Ar n
 input files before terminating.
 This operand is only applicable when the input device is a tape.
+.It Cm fillchar Ns = Ns Ar c
+When padding a block in conversion mode or due to use of
+.Cm noerror
+and
+.Cm sync
+modes, fill with the specified ASCII character, rather than using a space
+or nul.
 .It Cm ibs Ns = Ns Ar n
 Set the input block size to
 .Ar n
@@ -247,6 +254,10 @@ with
 bytes (or with spaces if a block oriented conversion value was
 specified) and processed as a normal input buffer.
 If the
+.Cm fillchar
+option is specified, the fill char provided on the command line will override
+the automatic selection of fill character.
+If the
 .Cm sync
 conversion is not specified, the input block is omitted from the output.
 On input files which are not tapes or pipes, the file offset