Manpage of duptape
Section: User Commands (1)
Updated: 31 January 1992
duptape, recordio - copy tapes, preserving record boundaries
] [-v] [-V]
copies one or more files from one tape to another, preserving record lengths.
The tape drives can reside on different machines.
Alternatively, you can copy from tape to disk and later back to tape.
is a script that uses
to do the actual copying.
is either a remote tape drive of the form:
or a local tape drive (containing no `:' characters).
Example A: Local copy:
% duptape /dev/nrst0 /dev/nrst2
Example B: Copy from local tape drive to remote host:
% duptape /dev/nrst0 somehost:/dev/nrst2
An EOF is written after each file copied,
the last file.
This is because
many (most?) device drivers will write an EOF when the drive is closed.
If your driver doesn't add an EOF, you'll have to explicitly add the final
EOF by hand (e.g. "mt weof").
If you wish to copy a tape from somewhere other than its beginning,
simply position the tape to the desired starting location before invoking
program is used as follows:
- recordio -r
reads a tape from
and writes each record length plus data to
- recordio -w
reads the length-prefixed records from
and writes the records to a tape on
A tape can be copied to disk, then back to tape,
% recordio -r < tape > diskfile
% recordio -w < diskfile > tape
The following are options for
- -b bufsize
Set the copy buffer size. Default is 32KB. Must be at least
as great as the longest record. Beware: many tape drivers enforce an
upper bound on the value of
even if the length of the actual records on tape are much smaller.
- -n neof
filemarks. The default is to read through the first double-EOF.
Note that the end of data on an Exabyte tape will act like a double EOF.
Don't copy zero-length files (that is, only write one EOF when there are
several EOF's in a row in the input tape).
The following are options for all commands:
Verbose mode. Writes number of EOF's to
is distinguished from
by indenting its verbose output with a tab.
and each record length
to also be written.
doesn't have a
option because the buffersize is passed
- When copying on remote host(s),
by default; thus, you must be able to execute
commands on the remote hosts.
You can override this with the environment variable DUPTAPE_RSH.
must also exist on both hosts.