man afclient (Administration système) - controls the client functions of the afbackup package


afclient - controls the client functions of the afbackup package


afclient -cxtd [-[RraunlOUvgIiqQZwbjGK]] [-D <destination>] [-M <message>] [-m <message-poll-interval>] [-h <backup-server>] [-z <proccmd> <unproccmd>] [-T <to-extract-file/tmpdir-for-copytape>] [-C <cartridge-number>] [-F <filenumber-on-tape>] [-f <archive-filename>] [-e <errorlog-filename>] [-p <server-port-number>] [-N <newer-than-filename>] [-o <user-ID>] [-k <encrption-key-file>] [-s <dont-process-filepattern> [-s ...]] [-H <header>] [-V <statistics-report-file>] [-A <after-time-seconds>] [-B <before-time-seconds>] [-W <identity>] [<files> <directories> ...]

afclient -X <program> [ -h <backup-client> ]

afclient -?

afclient -usage

The first form is similar to tar (1), except that it contacts a backup server, if the -f option is not supplied.

The second form is used to start a program remotely on another host. In most cases this will be one of:

afclient -X full_backup -h <some-host>

afclient -X incr_backup -h <some-host>

Normally this host is a backup client and a backup is started this way. Only programs can be started, that reside in the directory, that is configured in the backup server's configuration file unter "Program-Directory".

The third form produces the following help text:


This program is used to maintain archives on a backup server host or in a file. Archives can be created, extracted or their contents be listed. One of the following flags has always to be supplied:

to create an archive
to extract from an archive
to list the contents of an archive
to verify (compare) the contents of an archive
to set a certain cartridge on the backup server (makes only sense extracting or listing with -x or -t, the writing position can't be changed by clients)
to set a certain file on the backup server's tape (same applies as for -C )
to printout the current cartridge and tape file number on the backup server
to printout the cartridge and tape file number for the the next write access on the backup server
followed by the full path name of a program to be started on the client. This can be used to trigger a backup remotely. If the program needs arguments, the command together with the arguments has to be enclosed by quotes
to printout an index of the backups written to the current cartridge
to check the status of the streamer on the server side, e.g. whether it is ready and waiting for requests to service, see below for possible states
to request a new cartridge for the next writing operation. If the current writing position is already at the beginning of a new or reused tape, nothing happens
-D <destination>
to make an exact copy of a tape to another one (duplicate). See below how to specify the destination tape. Duplication can be either from one cartridge to another on the same server, or from one server to another one. When copying to the same server chunks of data are stored in a temporary directory on the client, where the command is started, what should preferably be the source server
-M <message>
Send a message to the server. Messages will in the most cases contain whitespace, so they should be enclosed in quotes. Server messages should be sent to the single stream server (port), the multi stream server might hang receiving a message due to systematical reasons. Several messages can be put into the string. They must be separated by a real newline character or the usual C-like n . The following messages are currently supported:
PreciousTapes: <list-of-tapes>
The list of tapes is inserted into the table with the tapes, that are crucial for clients to restore all files, that are listed in all existing index files. These tapes will not be overwritten until explicitly permitted. This message is generated automatically and should not be used in other user contexts
ReuseTapes: <list-of-tapes>
The opposite of PreciousTapes. Sending this message permits the server to overwrite the listed tapes, though they are crucial for some client
TapesReadOnly: <list-of-tapes>
The list of tapes is inserted into the file listing the files, that should not be written any more for whatever reason
TapesReadWrite: <list-of-tapes>
This reverts the status of tapes set read-only to read-write, the opposite of TapesReadOnly
When an operator is requested to do something the server is waiting for, this message can be sent to trigger the server to proceed. This message has the same effect as the cartready command
DeleteClient: <client-identifier>
The tapes, that are marked as reserved for a client to recover all the data in his indexes, are freed. That is, the appropriate line is removed from the server's precious_tapes file

-c, -x, -t, -d, -X, -d and -I are mutual exclusive. The other options can be supplied as needed. To set the cartridge and/or the tape file on the backup server is only making sense when not creating an archive. The serial order of writing to tape is handled by the server machine independently of the client.

More options in alphabetical order:

in combination with -c: read standard input and write it to tape, in combination with -x: read tape and write it to standard output
-A <time>
process files (save or extract) modified after the given time in seconds since 1.1.1970 00:00
in combination with -x : extract all files and directories in the archive
don't enter buffering mode
-B <time>
process files (save or extract) modified before the given time in seconds since 1.1.1970 00:00
-e <errlog>
Use the file <errlog> to write error messages to instead of the standard error output
-f <file>
write to or read from a file instead of querying the backup server
while extracting/reading: ignore leading garbage, suppress error messages at the beginning. This is useful when extracting from tape files, that are not the first ones of a whole archive.
-H <header>
put the supplied informational header to the begin of the backup. If a - is supplied (no space may follow -H i.e. -H-) the information is read from the first line of stdin. Backslash sequences of C-like style are replaced
-h <host>
use the backup server with the name <host> default host is the machine with the name backuphost
while extracting: ignore the stored ownership and do not restore it
when starting to write: request starting a new tape file
when packing, do not keep the access time of the file. By default after packing a filesystem entry it's previous atime is restored
-k <file>
use the contents of the given file as encryption key for authenticating to the server
for each packed or unpacked filename, if sending to or receiving from a backup server in verbose mode in combination with -n: printout server name and port number at the beginning of the line, e. g.: orion%2988!
-N <file>
while archiving: ignore files with a modification time before the one of the given file, only save newer files or such with the same age in seconds
for each packed or unpacked filename, if sending to or receiving from a backup server in verbose mode: printout cartridge and tape file number at the beginning of the line, e. g.: 7.15: <filename>

In combination with -X: precede each line of output received from the remotely started program with the identifier of the remote host and a colon, e. g.: darkstar: Full backup finished.
for each packed file creating a backup in verbose mode: printout the user-ID of the file owner at the beginning of the line prefixed with a bar | eventually behind cartridge and file number
-o <uid>
archive or extract only files owned by the user with the given user-ID (an integer)
-p <portno>
use a different port number for communicating with the backup server. Default is TCP-Port 2988
pack or extract directories recursively with all of their contents
use filenames relative to the current directory, whether they start with a slash or not. If -r is given more then 1 time, also let symlinks originally pointing to absolute paths now point to paths relative to the directory, where the symlink will be created
-S <cartset>
The cartridge set to use, where <cartset> is the number of a valid cartridge set on the server side. Default is 1. This option makes sense only when creating backups with -c
-s <filepat>
do not attempt processing on files matching the given filename pattern. This parameter may appear several times
-T <file>
read the filenames to process from the <file>. The filenames must be separated by whitespace. If whitespace is part of a filename, it has to be enclosed by double quotes. Double quotes or backslashes within the filename have to be preceded by a backslash. In combination with -D: the tape files to be copied are temporarily stored in the given directory instead of the default directory /tmp
for each packed file creating a backup in verbose mode: printout the modification time of the file in seconds since 1970/1/1 0:00 at the beginning of the line prefixed with a tilde ~ eventually behind cartridge number, file number and owner
while extracting: remove existing files with the same name as found in the archive. Otherwise no existing files are overwritten
-V <file>
write a report containing statistics at the end of a backup to the <file>
verbose mode: print the filenames while creating or extracting, be a little more verbose while listing contents. If -v is the only given flag: print out software name and version
-z <z> <uz>
use <z> as the command, that is used to process files, <uz> for the corresponding unprocess. The command has to read from stdin and to write to stdout. If arguments have to be supplied to <z> and/or <uz>, don't forget to use quotes. If built-in compression is desired, the command for processing has to start with a dot (.), followed by a space and a number ranging from 1 to 9, that specifies the compression level. If an additional external command should process the data, it may follow, separated from the compression level by whitespace. The order of processing is: First the external program processes the data, then built-in compression is applied. An empty string has to be supplied for <uz> (or any other dummy is ok), if only built-in compression is desired. Examples for <z>:

gzip (run external command gzip), "gzip -2" (the same with an argument), ". 8" (only built-in compression level 8), ". 3 __descrpt -k /my/key" (run command __descrpt and apply built-in compression level 3)
while printing out the contents: check those files in the archive that are processed for integrity. While creating an archive: write a CRC32 checksum for each file, file contents or command output to the backup stream
to printout this text


The names of the files and directories, that have to be put into or extracted from an archive are by default read from the standard input. If you supply filenames in the command line or enter the -a flag when extracting, standard input is not read. The same applies, when filenames are read from a file with the -T option. When reading the names from a file or from standard input, they must be given one per line. If a name contains special characters (like newline or nonprintable ones), they have to be specified using backslash-sequences like in C-code, e.g. \n for newline. In save mode ( -c ) filenames can be prefixed with character sequences, that have special meanings (no space between prefix and filename):

The file is not saved with all attributes present in the inode, but only the contents are saved. This might be useful for saving raw-devices
With /../ the configured processing is not applied to the file contents for safety reasons. With this prefix processing can be forced nonetheless
and a mandatory space character indicates, that the following characters up to (but not including) another triple bar ||| should be interpreted as a shell command, that is started and whose standard output is written to the backup. At restore time the command following the second triple bar is started and the data stream read at backup time is written to it's standard input. This might be useful for saving e.g. databases. The second command may be terminated by a triple sharp ###, that starts an optional comment. Example:
||| pg_dumpall ||| psql db_tmpl ### Store Postgres DBs


The -w option reports one of the following states, separated by the plus character + :

the device is not in use by any program and the server side is ready to service requests
the device is in use and currently operated by the afbackup service
the streamer device is in use by some program, that is not part of the afbackup service
the streamer device is not accessible or in some other way occupied
the device is not busy, but there is no tape loaded
when reported together with UNLOADED, a tape can be loaded quickly e.g. using the afclient command with option -C <cartno>. It is not considered quickly, if a human operator must put the cartridge into the drive, so in this case only UNLOADED is reported. When reported with READY, the tape can be changed quickly (same understanding as before).


The destination tape for the duplicate operation can be given in two ways: either with the options -h, -p, -C and -k following the -D immediately without space and enclosed in quotes, so that they appear as an own argument list in one real argument, e.g.:

 -D' -C 5 -h targethost -p targetport'
(double quotes are of course also possible ...).

The second format is as follows:


At least one of the specifiers must be present. Examples:


If one of the specifiers is omitted, it is assumed identical with the copy source specified in the normal options -h, -p, -C and -k. Copying a tape to itself is prevented.


Client configuration file
The directory for logging the client backups
Some internal state information of the client backups.



afbackup was written by Albert Fluegel ( This manpage was extracted from the text docs by Christian Meder (