Run shell substitutions in $ASTRALITY_CONFIG_HOME

astrality/config.py

@@ -56,6 +56,8 @@ def infer_config_location(
     config_directory: Optional[Path] = None,
 ) -> Tuple[Path, Path]:
     """
+    Return path of Astrality configuration file based on config folder path.
+
     Try to find the configuration directory and file for astrality, based on
     filesystem or specific environment variables if they are present several
     places to put it. If the expected config file is not present, use an
@@ -205,12 +207,16 @@ def expand_environment_variable(match: Match[str]) -> str:
 
 def insert_command_substitutions(content: str) -> str:
     """Replace all occurences in string: $(command) -> command stdout."""
+    working_directory = infer_config_location()[0].parent
 
     command_substitution_pattern = re.compile(r'\$\((.*)\)')
 
     def command_substitution(match: Match[str]) -> str:
         command = match.groups()[0]
-        result = run_shell(command=command)
+        result = run_shell(
+            command=command,
+            working_directory=working_directory,
+        )
         if result == '':
             logger.error(
                 f'Command substitution $({command}) returned empty stdout.'

docs/configuration.rst

@@ -66,15 +66,18 @@ Astrality makes two non-standard additions to the ``YAML`` syntax, so-called int
 
     Then the occurrence of ``${VAR1}`` in ``astrality.yaml`` will be replaced with ``run command`` and **not** ``run $VAR2``.
     If you want the ability to turn off this "recursive expansion" feature, `open an issue <https://github.com/JakobGM/astrality/issues>`_, and I will add configuration option for it.
-    
+
     .. caution::
         Only ``${NAME}`` blocks are expanded. ``$NAME`` will be left in place, to allow runtime expansions of environment variables when modules define shell commands to be run.
 
 .. _command_substitution:
 
-* **Command substitution**: 
+* **Command substitution**:
     ``$( some_shell_command )`` is replaced with the standard output resulting from running ``some_shell_command`` in a ``bash`` shell.
 
+    .. note::
+        Shell commands are run from ``$ASTRALITY_CONFIG_HOME``. If you need to refer to paths outside this directory, you can use absolute paths, e.g. ``$( cat ~/.home_directory_file )``.
+
 .. note::
 
     Interpolations in ``astrality.yaml`` occur on Astrality startup, and will not reflect changes to environment variables and shell commands after startup.