bitbake handbook

http://www.openembedded.org/wiki/Main_Page

Useful bitbake commands (from https://community.nxp.com)/docs/DOC-94953)

	Description
bitbake	Bake an image (add -k to continue building even errors are found in the tasks execution)
bitbake -c	Execute a particular package's task. Default Tasks names: fetch, unpack, patch, configure, compile, install, package, package_write, and build. Example: To (force) compiling a kernel and then build, type: $ bitbake  linux-imx -f -c compile $ bitbake linux-imx
bitbake -g -u depexp	Show the package dependency for image. Example: To show all packages included on fsl-image-gui $ bitbake fsl-image-gui -g -u depexp NOTE: This command will open a UI window, so it must be execute on a console inside the host machine (either virtual or native).
bitbake -c  devshell	Open a new shell where with neccesary system values already defined for package
hob	bitbake frontend/GUI.
bitbake -c listtasks	List all tasks for package
bitbake virtual/kernel -c menuconfig	Interactive kernel configuration
bitbake -c fetchall	Fetch sources for a particular image
bitbake-layers show-layers	Show layers
bitbake-layers show-recipes "*-image-*"	Show possible images to bake. Without "*-images-*", it shows ALL recipes
bitbake -g <image> && cat pn-depends.dot | grep -v -e '-native' | grep -v digraph | grep -v -e '-image' | awk '{print $1}' | sort | uniq	Show image's packages
bitbake -g <pkg> && cat pn-depends.dot | grep -v -e '-native' | grep -v digraph | grep -v -e '-image' | awk '{print $1}' | sort | uniq bitbake -g <packagename> -u taskexp	Show package's dependencies
bitbake –v 2>&1 | tee image_build.log	Print (on console) and store verbose baking
bitbake -s | grep	Check if certain package is present on current Yocto Setup

Bitbake Cheat Sheet

(from https://elinux.org/Bitbake_Cheat_Sheet)

Here are some quick notes on bitbake syntax and rules. For an exhaustive list of functionality, and longer descriptions, see the bitbake manual at: http://www.yoctoproject.org/docs/latest/bitbake-user-manual/bitbake-user-manual.html

Contents

• 1 Command Line options
• 2 User interfaces
• 3 .bb file syntax
• 4 Additional bitbake-related commands

Command Line options

Here are a few commonly-used command line options.

Option	Meaning
-c	execute for the image or recipe being built. ex: bitbake -c fetch busybox. Some of the possible tasks are: fetch, configure, compile, package, clean
-f	force execution of the operation, even if not required
-v	show verbose output
-DDD	show lots of debug information
-s	show recipe version information
--help	get usage help
-c listtasks	show the tasks associated with an image or individual recipe
-g	output dependency tree in graphviz format

User interfaces

Bitbake can be used with several different user interfaces. Here are some options:

User interface	Type	NOTES
bitbake or "bitbake -u knotty "	scrolling text interface	This is the default user interface
bitbake -u ncurses	text-window based interface	I couldn't figure out how to control or exit this interface
bitbake -u hob	graphical interface	This is a full graphical interface which includes selecting machine, distro, etc. and performing a build
bitbake -u goggle	simple graphical interface	This is a simple graphical wrapper over the streaming text output of bitbake. It's nice in that it shows collapsible trees for the logs for sub-tasks for each recipe.

.bb file syntax

This table lists some of the syntax found in recipe (.bb) files.

Syntax	Meaning	NOTES
VAR = "foo"	simple assignment
VAR ?= "foo"	assign if no other value is already assigned (default assignment)
VAR ??=foo	weak default assignment	takes lower precedence than ?=
VAR = "stuff ${OTHER_VAR} more"	variable expansion	OTHER_VAR expanded at time of reference to VAR
VAR := "stuff ${OTHER_VAR} more"	immediate variable expansion	OTHER_VAR expanded at time of parsing this line
VAR += "foo"	append with space
VAR =+ "foo"	prepend with space
VAR .= "foo"	append without space
VAR =. "foo"	prepend without space
VAR_append = "foo"	append without space
OVERRIDES="string1:string2" VAR = "foo" VAR_string1 = "bar"	alternate/override value	if string1 is listed in OVERRIDES, use "bar" for value of VAR, otherwise use "foo"
OVERRIDES="string1:string2" VAR = "foo" VAR_append_string1 = " bar"	conditional append	if string1 is in OVERRIDES, then append " bar" to the value of VAR
BBVERSIONS="1.0 1.8 string" VAR="foo" VAR_string="bar"	range-specific conditional	If the version of the package is in the specified range (1.0-1.8 in this example), then perform an override on the indicated variable
VAR = "foo ${@}"	python code expansion	ex: VAR = "the date is: ${@time.strftime(’%Y%m%d’,time.gmtime())}"
include foo	include file	include file named "foo", search BBPATH
require []foo	require file	include file named "foo", failing if not found exactly where specified
inherit foo	inherit classes	include definitions from foo.bbclass
do_sometask() { }	define a task using shell code
python do_sometask { }	define a task using python code
addtask sometask (before|after) other_task	add a task	adds a defined task to the list of tasks, with the ordering specified. Zero or more 'before' or 'after' clauses can be used.
VAR[some_flag]="foo"	associate a subsidiary flag value to a variable	a few subsidiary flag value names are well-defined: "dirs", "cleandirs", "noexec", "nostamp", "fakeroot", "umask", "deptask", "rdeptask", "recdeptask", "recrdeptask" Flag values appear to be used exclusively with task definitions (i.e. do_sometask)
inherit externalsrc EXTERNALSRC = "/some/path" # EXTERNALSRC_BUILD = "/some/path"	Fetch source from /some/path	You can place this at the bottom of a .bb or .bbappend file to override where the source will be fetched from. This is very convenient if you are currently working on the source code. Depending on the type of build (eg, 'inherit module' for out of tree Linux kernel modules) you may or may not need to set EXTERNALSRC_BUILD.

Additional bitbake-related commands

Command	Description	NOTES
bitbake-layers	Show information about layers and recipes	Included in the bitbake/bin directory in yocto.
bitbake-env	Show invidividual bitbake variable values	see: http://www.crashcourse.ca/wiki/index.php/OE_bitbake-env_utility
bitbake -g -u depexp	Show dependency information in a graphical interface