xauth(X)

xauth -- X authority file utility

Syntax

xauth [ -f authfile ] [ -vqib ] [ command arg . . . ]

Description

The xauth program is used to edit and display the authorization information 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.

Options

The following options may be used with xauth. They may be given individually (for example, -q -i) or may combined (for example, -qi).

-b: xauth attempts to break any authority file locks before proceeding and should only be used to clean up stale locks
-f authfile: specifies the name of the authority file to use. By default, xauth uses the file specified by the XAUTHORITY environment variable or .Xauthority in the user's home directory.
-i: xauth ignores any authority file locks. Normally, xauth refuses to read or edit any authority files that have been locked by other programs (usually xdm or another xauth).
-q: xauth operates quietly and does 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.
-v: xauth operates verbosely and prints 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 output is directed to a terminal.

Commands

The following commands may be used to manipulate authority files:

add displayname protocolname hexkey: adds an authorization entry for the indicated display using the given protocol and key data to the authorization file. The data is specified as an even-lengthed string of hexadecimal digits, each pair representing one octet. The first digit gives the most significant 4 bits of the octet and the second digit gives the least significant 4 bits. A protocol name consisting of just a single period is treated as an abbreviation for MIT-MAGIC-COOKIE-1
[n]extract filename: writes authorization entries for each of the specified displays 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 are written to the standard output.
[n]list [displayname . . .]: prints authorization entries for each of the specified displays (or all if no displays are named) on the standard output. If the nlist command is used, entries are 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 . . .]: reads authorization entries from the specified files and merges them into the authorization database, superseding any matching existing entries. If the nmerge command is used, the numeric format given in the description of the extract command is used. If filename is a single dash, the standard input is read if it hasn't already been read by another command.
remove displayname . . .: removes authorization entries matching the specified displays from the authority file
source filename: treats filename as a script containing xauth commands to execute. Blank lines and lines beginning with a sharp sign ``#'' are ignored. If filename is a single dash the standard input is read if it hasn't already been read by another command.
info: prints to standard output information describing the authorization file, whether or not any changes have been made, and the source of the xauth commands
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: exits the program, ignoring any modifications. This may also be accomplished by pressing the interrupt character.
help [string]: prints descriptions of all commands that begin with the given string (or all commands if no string is given) on the standard output.
?: prints a short list of the valid commands 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 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.

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 variables

This xauth program uses the following environment variables:

XAUTHORITY: to get the name of the authority file to use if the -f option is not used.
HOME: to get the user's home directory if XAUTHORITY is not defined.

Files

: $HOME/.Xauthority default authority file if XAUTHORITY is not defined

Known limitations

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.