README.md: Improve config variable documentation (#24)

pull/25/head
Joseph Carter 2016-10-05 14:56:45 -07:00 committed by XECDesign
parent 7f0c59d5c1
commit 1d18e27f9c
1 changed files with 24 additions and 4 deletions

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@ -14,10 +14,30 @@ environment variables.
The following environment variables are supported:
* `IMG_NAME`, the name of the distribution to build (required)
* `APT_PROXY`, proxy/cache URL to be included in the build
* `MAX_STAGE`, to only run up to this stage. (default `4`, eg: `MAX_STAGE=2`)
* `RUN_STAGE`, to only run a single stage (eg: `RUN_STAGE=1`)
* `IMG_NAME` **required** (Default: unset)
The name of the image to build with the current stage directories. Setting
`IMG_NAME=Raspbian` is logical for an unmodified RPi-Distro/pi-gen build,
but you should use something else for a customized version. Export files
in stages may add suffixes to `IMG_NAME`.
* `APT_PROXY` (Default: unset)
If you require the use of an apt proxy, set it here. This proxy setting
will not be included in the image, making it safe to use an `apt-cacher` or
similar package for development.
* `MAX_STAGE` (Default: unset)
Set this to the number of the highest stage you wish to build. For
Raspbian, `MAX_STAGE=2` will build Raspbian-lite and then stop.
* `RUN_STAGE` (Default: unset)
Build only a single stage. Does not build prior or subsequent stages.
Building with e.g. `RUN_STAGE=3` requires that a build of stage2 already
exists. *Note: Be aware that the image date affects whether or not the
prior stages will be found!*
A simple example for building Raspbian: