Build PlatformIO projects with an arbitrary source code structure. This will create a new temporary project which the source code will be copied into. More information: https://docs.platformio.org/en/latest/core/userguide/cmd_ci.html.
pio ci path/to/project
pio ci --lib path/to/library_directory path/to/project
pio boards
lists all of them):pio ci --board board path/to/project
pio ci --build-dir path/to/build_directory path/to/project
pio ci --keep-build-dir path/to/project
pio ci --project-conf path/to/platformio.ini