Commit c58b46cb authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)

Documentation: bootconfig: Add bootconfig override operator

Add a sentence about bootconfig override operator (":=") to
bootconfig.rst.

Link: https://lkml.kernel.org/r/159482884682.126704.7198860675721719878.stgit@devnote2Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 81464192
...@@ -71,6 +71,16 @@ For example,:: ...@@ -71,6 +71,16 @@ For example,::
foo = bar, baz foo = bar, baz
foo = qux # !ERROR! we can not re-define same key foo = qux # !ERROR! we can not re-define same key
If you want to update the value, you must use the override operator
``:=`` explicitly. For example::
foo = bar, baz
foo := qux
then, the ``qux`` is assigned to ``foo`` key. This is useful for
overriding the default value by adding (partial) custom bootconfigs
without parsing the default bootconfig.
If you want to append the value to existing key as an array member, If you want to append the value to existing key as an array member,
you can use ``+=`` operator. For example:: you can use ``+=`` operator. For example::
...@@ -84,6 +94,7 @@ For example, following config is NOT allowed.:: ...@@ -84,6 +94,7 @@ For example, following config is NOT allowed.::
foo = value1 foo = value1
foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist
foo.bar := value2 # !ERROR! even with the override operator, this is NOT allowed.
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