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://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" |
alternate/override value | if string1 is listed in OVERRIDES, use "bar" for value of VAR, otherwise use "foo" |
OVERRIDS="string1:string2" VAR = "foo" |
conditional appending | if string1 in in OVERRIDES, then append " bar" to the value of VAR |