mdtar(1)
NAME
mdtar − multiple diskette archiver
SYNTAX
mdtar [ key ] [ name ... ]
DESCRIPTION
The mdtar command saves multiple files on multiple archives (usually an RX50 diskette, but any file/device may be specified). mdtar actions are controlled by the key argument. The key is a string of characters containing one function letter and one or more function modifiers. Other arguments to mdtar are file or directory names specifying which files to dump or restore. In all cases, appearance of a directory name refers to the files and, recursively, subdirectories of that directory. mdtar also saves special files.
The function portion of the key is specified by a letter.
c Create a new archive. Writing begins at the beginning of the archive instead of after the last file.
r Write the named files to the end of the archive.
t Produce a Table of Contents listing the names of the designated files each time they occur on the archive. If no file argument is given, all of the names on the archive are listed. Produce a Table of contents.
u Update the current archive. Adds the named files to the archive, if they are not there already or if they have been modified since last put on the archive.
x Extract the named files from the archive. If the named file matches a directory whose contents had been written onto the archive, this directory is recursively extracted. The owner, modification time, and mode are restored if you are the superuser and if you have also specified the p switch. If no file argument is given, the entire content of the archive is extracted. If multiple entries specifying the same file are on the archive, the last one overwrites previous versions.
The following characters may be used to qualify the function desired in addition to one or more of the above letters.
0...9 Select unit number of the drive as an alternate disk drive. The default disk drive is the device named /dev/rra1a.
A Use the next argument as the "Archive" number to begin output. This switch is intended for error recovery. mdtar outputs files in terms of Archives. Each Archive contains a number of files. If mdtar has been requested to dump a path (set of files) that consist of (for example) 10 archives and there is an error writing the nth Archive, then the A modifier may be used to restart mdtar at the nth Archive.
CAUTION
You must issue the same path (set of files) as in the first command. This will guarantee that mdtar will begin at the correct file on Archive n.
If the v mode is specified, mdtar outputs informational messages to inform the user of progress. For example, the following command will dump the entire directory structure:
mdtar cv
If an error occurs on Archive 7, to restart at the 7th Archive, without having to re-dump the first 6 Archives, issue the following command:
mdtar cvA 7
mdtar will tell you it is skipping the first 6 Archives and will resume output with the data that begins Archive 7.
b Use the next argument as the blocking factor for archive records. The default is 20 (the maximum is 1024).
B Forces output blocking to 20 blocks per record.
f Use the next argument as the name of the archive instead of the /dev/rra1a default. If the name of the file is −, tar writes to standard output (piping).
F[ F ] operate in fast mode. When F is specified, mdtar skips all SCCS directories, core files, and errs files. When FF is specified, mdtar also skips all a.out and *.o files.
h Save a copy of the file on the output device and do not save symbolic link information. The default action of mdtar is to place symbolic link information on the output device. A copy of the file IS NOT saved on the output device.
i Ignore checksum errors found in the archive.
l Print an error message if all links to the files dumped cannot be resolved. If -l is not specified, no error messages are printed.
m Do not restore the modification times. The modification time is the time of extraction. Normally, mdtar restores modification times of regular and special files.
o Suppress the normal directory information. On output, mdtar normally places information specifying owner and modes of directories in the archive. Former versions of tar, when encountering this information will give the error message
<name>/: cannot create.
p Restore the named files to their original modes, ignoring the present umask (2). Setuid and sticky information will also be restored to the super-user. You must be Superuser to perform this option. (See stat(2), S_ISVTX)
s The next argument specifies the size of the output archive media in blocks (each block contains 512 bytes). This enables mdtar to be used with devices of different physical media sizes. The default is 800 blocks (assumption is an RX50 output Archive).
v Write the name of each file treated, preceded by the function letter, to diagnostic output. Normally mdtar does its work silently. With the t function, the verbose option gives more information about the archive entries than just their names.
w Print the action to be taken followed by file name, then wait for user confirmation. If a word beginning with ‘y’ is given, the action is done. Any other input means do not do it.
If a file name is preceded by −C, then mdtar will perform a chdir (2) to that file name. This allows multiple directories not related by a close common parent, to be archived using short relative path names. For example, to archive files from /usr/include and from /etc, one might use
tar c -C /usr include . -C /etc .
RESTRICTIONS
The u option can be slow.
The current limit on file name length is 100 characters.
There is no way to follow symbolic links selectively.
DIAGNOSTICS
Indicates bad key characters and archive read/write errors.
Indicates if enough memory is not available to hold the link tables.
FILES
/tmp/tar*