53 lines
1.0 KiB
Markdown
53 lines
1.0 KiB
Markdown
# Configuration file syntax
|
|
|
|
```sh
|
|
# VAR value (the brackets are mandatory)
|
|
${VAR}
|
|
|
|
# Set value if not defined (ie set default value)
|
|
VAR ?= "defvalue"
|
|
|
|
# Set value at the end of parsing if the value is not defined
|
|
VAR ??= "defvalue"
|
|
|
|
# Set VAR to "value" immediately
|
|
VAR := "value"
|
|
|
|
|
|
# Append "value" to VAR
|
|
# Warning: inserts a space between current value and appended value
|
|
VAR += "value"
|
|
# Same with prepend:
|
|
VAR =+ "value"
|
|
|
|
# Same to append/prepend but without space
|
|
VAR .= "value"
|
|
VAR =. "value"
|
|
|
|
# Same to append/prepend
|
|
# but without space and deferred at the end of parsing
|
|
VAR_append = "value"
|
|
VAR_prepend = "value"
|
|
|
|
# Remove elements (words) in a space-separated value list
|
|
VAR_remove = "value"
|
|
|
|
|
|
# Like bash functions
|
|
my_function() {
|
|
echo "Hello world"
|
|
}
|
|
# Note that _append suffix also works with functions
|
|
|
|
|
|
# Function written in python
|
|
python my_function2() {
|
|
print "Hello world"
|
|
}
|
|
```
|
|
|
|
<warn data-markdown>
|
|
- `${VAR}` is a Yocto variable.
|
|
- `$VAR` is a shell variable.
|
|
- They are very different !
|
|
</warn> |