xauth(1X)xauth(1X)NAMExauth - X authority file utility
SYNOPSISxauth [-f authfile] [-vqib] [commandarg...]
OPTIONS
The following options may be used with xauth. They may be given indi‐
vidually (for example, -q -i) or may combined (for example, -qi). This
option specifies the name of the authority file to use. By default,
xauth will use the file specified by the XAUTHORITY environment vari‐
able or in the user's home directory. This option indicates that xauth
should operate quietly and not print unsolicited status messages. This
is the default if an xauth command is given on the command line or if
the standard output is not directed to a terminal. This option indi‐
cates that xauth should operate verbosely and print status messages
indicating the results of various operations (for example, 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 out‐
put is directed to a terminal. 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 or another xauth). This option indicates that xauth
should attempt to break any authority file locks before proceeding.
Use this option only to clean up stale locks.
DESCRIPTION
The xauth program is used to edit and display the authorization infor‐
mation used in connecting to the X server. This program is usually
used to extract authorization records from one machine and merge them
in on another (as is the case when using remote logins or granting
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. Normally xauth is not used
to create the authority file entry in the first place; xdm does that.
COMMANDS
The following commands may be used to manipulate authority files: 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 represent‐
ing one octet. The first digit of each pair gives the most significant
4 bits of the octet, and the second digit of the pair gives 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. 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 filename consists of just a single
dash, the entries will be written to the standard output. Authoriza‐
tion 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. 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 has not been read before. Authorization entries matching
the specified displays are removed from the authority file. The speci‐
fied 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 has not
already been read. Information describing the authorization file,
whether or not any changes have been made, and from where xauth com‐
mands are being read is printed on the standard output. If any modifi‐
cations 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. The program exits, ignoring any modifications. This may also
be accomplished by pressing the interrupt character. 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
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 informa‐
tion (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 host‐
name/unix:displaynumber so that local entries for different machines
may be stored in one authority file.
EXAMPLE
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:
% xauth extract - $DISPLAY | rsh otherhost xauth merge -
ENVIRONMENT
This xauth program uses the following environment variables: to get the
name of the authority file to use if the -f option is not used. to get
the user's home directory if XAUTHORITY is not defined.
FILES
default authority file if XAUTHORITY is not defined.
BUGS
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.
AUTHOR
Jim Fulton, MIT X Consortium
xauth(1X)
