'\" t .TH "HWDB" "7" "" "systemd 254" "hwdb" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" hwdb \- Hardware Database .SH "DESCRIPTION" .PP The hardware database is a key\-value store for associating modalias\-like keys to udev\-property\-like values\&. It is used primarily by udev to add the relevant properties to matching devices, but it can also be queried directly\&. .SH "HARDWARE DATABASE FILES" .PP The hwdb files are read from the files located in the system hwdb directory /lib/udev/hwdb\&.d and the local administration directory /etc/udev/hwdb\&.d\&. All hwdb files are collectively sorted and processed in lexical order, regardless of the directories in which they live\&. However, files with identical filenames replace each other\&. Files in /etc/ have the highest priority and take precedence over files with the same name in /lib/\&. This can be used to override a system\-supplied hwdb file with a local file if needed; a symlink in /etc/ with the same name as a hwdb file in /lib/, pointing to /dev/null, disables that hwdb file entirely\&. hwdb files must have the extension \&.hwdb; other extensions are ignored\&. .PP Each hwdb file contains data records consisting of matches and associated key\-value pairs\&. Every record in the hwdb starts with one or more match strings, specifying a shell glob to compare the lookup string against\&. Multiple match lines are specified in consecutive lines\&. Every match line is compared individually, and they are combined by OR\&. Every match line must start at the first character of the line\&. .PP Match patterns consist of literal characters, and shell\-style wildcards: .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} Asterisk "*" matches any number of characters .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} Question mark "?" matches a single character .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} Character list "[\fIchars\fR]" matches one of the characters \fIchars\fR listed between "[" and "]"\&. A range may be specified as with a dash as "[\fIfirst\fR\-\fIlast\fR]"\&. The match may be inverted with a caret "[^\&...]"\&. .RE .PP The match lines are followed by one or more key\-value pair lines, which are recognized by a leading space character\&. The key name and value are separated by "="\&. An empty line signifies the end of a record\&. Lines beginning with "#" are ignored\&. .PP In case multiple records match a given lookup string, the key\-value pairs from all records are combined\&. If a key is specified multiple times, the value from the record with the highest priority is used (each key can have only a single value)\&. The priority is higher when the record is in a file that sorts later lexicographically, and in case of records in the same file, later records have higher priority\&. .PP The content of all hwdb files is read by \fBsystemd-hwdb\fR(8) and compiled to a binary database located at /etc/udev/hwdb\&.bin, or alternatively /lib/udev/hwdb\&.bin if you want ship the compiled database in an immutable image\&. During runtime, only the binary database is used\&. .SH "EXAMPLES" .PP \fBExample\ \&1.\ \&General syntax of hwdb files\fR .sp .if n \{\ .RS 4 .\} .nf # /lib/udev/hwdb\&.d/example\&.hwdb # Comments can be placed before any records\&. This is a good spot # to describe what that file is used for, what kind of properties # it defines, and the ordering convention\&. # A record with three matches and one property mouse:*:name:*Trackball*:* mouse:*:name:*trackball*:* mouse:*:name:*TrackBall*:* ID_INPUT_TRACKBALL=1 # The rule above could be also be written in a form that # matches Tb, tb, TB, tB: mouse:*:name:*[tT]rack[bB]all*:* ID_INPUT_TRACKBALL=1 # A record with a single match and five properties mouse:usb:v046dp4041:name:Logitech MX Master:* MOUSE_DPI=1000@166 MOUSE_WHEEL_CLICK_ANGLE=15 MOUSE_WHEEL_CLICK_ANGLE_HORIZONTAL=26 MOUSE_WHEEL_CLICK_COUNT=24 MOUSE_WHEEL_CLICK_COUNT_HORIZONTAL=14 .fi .if n \{\ .RE .\} .PP \fBExample\ \&2.\ \&Overriding of properties\fR .sp .if n \{\ .RS 4 .\} .nf # /lib/udev/hwdb\&.d/60\-keyboard\&.hwdb evdev:atkbd:dmi:bvn*:bvr*:bd*:svnAcer*:pn*:* KEYBOARD_KEY_a1=help KEYBOARD_KEY_a2=setup KEYBOARD_KEY_a3=battery # Match vendor name "Acer" and any product name starting with "X123" evdev:atkbd:dmi:bvn*:bvr*:bd*:svnAcer:pnX123*:* KEYBOARD_KEY_a2=wlan # /etc/udev/hwdb\&.d/70\-keyboard\&.hwdb # disable wlan key on all at keyboards evdev:atkbd:* KEYBOARD_KEY_a2=reserved PROPERTY_WITH_SPACES=some string .fi .if n \{\ .RE .\} .PP If the hwdb consists of those two files, a keyboard with the lookup string "evdev:atkbd:dmi:bvnAcer:bdXXXXX:bd08/05/2010:svnAcer:pnX123" will match all three records, and end up with the following properties: .sp .if n \{\ .RS 4 .\} .nf KEYBOARD_KEY_a1=help KEYBOARD_KEY_a2=reserved KEYBOARD_KEY_a3=battery PROPERTY_WITH_SPACES=some string .fi .if n \{\ .RE .\} .SH "SEE ALSO" .PP \fBsystemd-hwdb\fR(8)