Bitbake Cheat Sheet

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Revision as of 19:52, 30 October 2012 by Tim Bird (Talk | contribs) (Syntax)

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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://docs.openembedded.org/bitbake/html/ (note that this link goes to the OpenEmbedded version of the bitbake manual, which is a version from 2006 as of this writing. A separate (yocto-specific?) bitbake manual is included in source form in the yocto project source directory, under bitbake/doc.)

Options

Option Meaning
-c <task> execute <task> 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 <image-or-recipe-name> show the tasks associated with an image or individual recipe
-g <recipe> output dependency tree in graphviz format

Syntax

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
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_appends_string1 = " bar"

conditional appending if string1 is in OVERRIDES, then append " bar" to the value of VAR