'\" t
.TH "BINFMT\&.D" "5" "" "systemd 254" "binfmt.d"
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.SH "NAME"
binfmt.d \- Configure additional binary formats for executables at boot
.SH "SYNOPSIS"
.PP
/etc/binfmt\&.d/*\&.conf
.PP
/run/binfmt\&.d/*\&.conf
.PP
/usr/lib/binfmt\&.d/*\&.conf
.SH "DESCRIPTION"
.PP
At boot,
\fBsystemd-binfmt.service\fR(8)
reads configuration files from the above directories to register in the kernel additional binary formats for executables\&.
.SH "CONFIGURATION FORMAT"
.PP
Each file contains a list of binfmt_misc kernel binary format rules\&. Consult the kernel\*(Aqs
\m[blue]\fBKernel Support for miscellaneous Binary Formats (binfmt_misc)\fR\m[]\&\s-2\u[1]\d\s+2
documentation file for more information on registration of additional binary formats and how to write rules\&.
.PP
Empty lines and lines beginning with
";"
and
"#"
are ignored\&. Note that this means you may not use those symbols as the delimiter in binary format rules\&.
.SH "CONFIGURATION DIRECTORIES AND PRECEDENCE"
.PP
Configuration files are read from directories in
/etc/,
/run/,
/usr/local/lib/, and
/usr/lib/, in order of precedence, as listed in the SYNOPSIS section above\&. Files must have the
"\&.conf"
extension\&. Files in
/etc/
override files with the same name in
/run/,
/usr/local/lib/, and
/usr/lib/\&. Files in
/run/
override files with the same name under
/usr/\&.
.PP
All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in\&. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence\&. Thus, the configuration in a certain file may either be replaced completely (by placing a file with the same name in a directory with higher priority), or individual settings might be changed (by specifying additional settings in a file with a different name that is ordered later)\&.
.PP
Packages should install their configuration files in
/usr/lib/
(distribution packages) or
/usr/local/lib/
(local installs)\&. Files in
/etc/
are reserved for the local administrator, who may use this logic to override the configuration files installed by vendor packages\&. It is recommended to prefix all filenames with a two\-digit number and a dash, to simplify the ordering of the files\&. It is recommended to use the range 10\-40 for configuration files in
/usr/
and the range 60\-90 for configuration files in
/etc/
and
/run/, to make sure that local and transient configuration files will always take priority over configuration files shipped by the OS vendor\&.
.PP
If the administrator wants to disable a configuration file supplied by the vendor, the recommended way is to place a symlink to
/dev/null
in the configuration directory in
/etc/, with the same filename as the vendor configuration file\&. If the vendor configuration file is included in the initrd image, the image has to be regenerated\&.
.SH "EXAMPLE"
.PP
\fBExample\ \&1.\ \&/etc/binfmt\&.d/wine\&.conf example:\fR
.sp
.if n \{\
.RS 4
.\}
.nf
# Start WINE on Windows executables
:DOSWin:M::MZ::/usr/bin/wine:
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsystemd-binfmt.service\fR(8),
\fBsystemd-delta\fR(1),
\fBwine\fR(8)
.SH "NOTES"
.IP " 1." 4
Kernel Support for miscellaneous Binary Formats (binfmt_misc)
.RS 4
\%https://docs.kernel.org/admin-guide/binfmt-misc.html
.RE