xauth(1) manual page
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xauth - X authority file utility
xauth [ -f authfile ] [ -v
] [ -q ] [ -i ] [ -b ] [command arg...]
The xauth program is used
to edit and display the authorization information used in connecting to
the X server. This program is usually to extract authorization records
from one machine and merge them in on another (as is the case when using
remote logins or to grant access to other users). Commands (described below)
may be entered interactively, on the xauth command line, or in scripts.
Note that this program does not contact the X server.
The following
options may be used with xauth. They may be given individually (e.g. -q -i)
or may combined (e.g. -qi):
- -f authfile
- This option specifies the name of the
authority file to use. By default, xauth will use the file specified by
the XAUTHORITY environment variable or .Xauthority in the user’s home directory.
- -q
- This option indicates that xauth should operate quietly and not print
unsolicited status messages. This is the default if an xauth command is
is given on the command line or if the standard output is not directed
to a terminal.
- -v
- This option indicates that xauth should operate verbosely
and print status messages indicating the results of various operations
(e.g. how many records have been read in or written out). This is the default
if xauth is reading commands from its standard input and its standard output
is directed to a terminal.
- -i
- This option indicates that xauth should ignore
any authority file locks. Normally, xauth will refuse to read or edit any
authority files that have been locked by other programs (usually xdm(1)
or another xauth).
- -b
- This option indicates that xauth should attempt to
break any authority file locks before proceeding and should only be used
to clean up stale locks.
The following commands may be used to manipulate
authority files:
- add displayname protocolname hexkey
- An authorization entry
for the indicated display using the given protocol and key data is added
to the authorization file. The data is specified as an even-lengthed string
of hexadecimal digits, each pair representing one octet. The first digit
of each pair gives the most significant 4 bits of the octet and the second
digit of the pairgives the least significant 4 bits. For example, a 32
character hexkey would represent a 128-bit value. A protocol name consisting
of just a single period is treated as an abbreviation for MIT-MAGIC-COOKIE-1.
- add displayname protocolname ’string’
- An authorization entry for the indicated
display using the given protocol and the protocolname is specified by ’string’.
If the authorization name is UN_DE-1, then the data field contains an ASCII
netname.
- [n]extract filename displayname...
- Authorization entries for each
of the specified displays are written to the indicated file. If the nextract
command is used, the entries are written in a numeric format suitable for
non-binary transmission (such as secure electronic mail). The extracted
entries can be read back in using the merge and nmerge commands. If the
the filename consists of just a single dash, the entries will be written
to the standard output.
- [n]list [displayname...]
- Authorization entries for
each of the specified displays (or all if no displays are named) are printed
on the standard output. If the nlist command is used, entries will be shown
in the numeric format used by the nextract command; otherwise, they are
shown in a textual format. Key data is always displayed in the hexadecimal
format given in the description of the add command.
- [n]merge [filename...]
- Authorization entries are read from the specified files and are merged
into the authorization database, superceding any matching existing entries.
If the nmerge command is used, the numeric format given in the description
of the extract command is used. If a filename consists of just a single
dash, the standard input will be read if it hasn’t been read before.
- remove
displayname...
- Authorization entries matching the specified displays are removed
from the authority file.
- source filename
- The specified file is treated as
a script containing xauth commands to execute. Blank lines and lines beginning
with a sharp sign (#) are ignored. A single dash may be used to indicate
the standard input, if it hasn’t already been read.
- info
- Information describing
the authorization file, whether or not any changes have been made, and
from where xauth commands are being read is printed on the standard output.
- exit
- If any modifications have been made, the authority file is written
out (if allowed), and the program exits. An end of file is treated as an
implicit exit command.
- quit
- The program exits, ignoring any modifications.
This may also be accomplished by pressing the interrupt character.
- help
[string]
- A description of all commands that begin with the given string
(or all commands if no string is given) is printed on the standard output.
- ?
- A short list of the valid commands is printed on the standard output.
Display names for the add, [n]extract, [n]list, [n]merge,
and remove commands use the same format as the DISPLAY environment variable
and the common -display command line argument. Display-specific information
(such as the screen number) is unnecessary and will be ignored. Same-machine
connections (such as local-host sockets, shared memory, and the Internet
Protocol hostname localhost) are referred to as hostname/unix:displaynumber
so that local entries for different machines may be stored in one authority
file.
The most common use for xauth is to extract the entry for the
current display, copy it to another machine, and merge it into the user’s
authority file on the remote machine:
example% xauth extract - $DISPLAY | rsh other xauth merge -
This xauth program uses the following environment variables:
- XAUTHORITY
- to get the name of the authority file to use if the -f option
isn’t used. If this variable is not set, xauth will use .Xauthority in the
user’s home directory.
- HOME
- to get the user’s home directory if XAUTHORITY
isn’t defined.
Users that have unsecure networks should take care to
use encrypted file transfer mechanisms to copy authorization entries between
machines. Similarly, the MIT-MAGIC-COOKIE-1 protocol is not very useful in
unsecure environments. Sites that are interested in additional security
may need to use encrypted authorization mechanisms such as Kerberos.
Spaces
are currently not allowed in the protocol name. Quoting could be added
for the truly perverse.
Copyright 1989, Massachusetts Institute
of Technology.
See X11(7)
for a full statement of rights and permissions.
Jim Fulton,
MIT X Consortium
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