Command Line Reference

Calling any Python function from the shell

python -m fargv <module.callable> invokes any importable Python callable directly from the shell. Parameter types and defaults are inferred from the function’s signature — no wrapper code needed.

python -m fargv numpy.linspace --help
python -m fargv numpy.linspace -s 0 -S 6.283 --num 8 --endpoint false

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fargv.parse — built-in flags

Every script that uses fargv.parse automatically receives the following parameters (all can be individually disabled with auto_define_*=False):

--help / -h

Print a formatted help message and exit.

python myscript.py --help

--bash_autocomplete

Print a bash completion script and exit.

source <(python myscript.py --bash_autocomplete)

--verbosity / -v (count switch)

Set the verbosity level. Can be specified as a count switch (-vvv = 3) or explicitly (--verbosity=2).

python myscript.py -vvv        # verbosity = 3
python myscript.py --verbosity=2

--config

Path to a JSON config file. Values in the file override coded defaults but are themselves overridden by any CLI flags that follow.

python myscript.py --config=~/.myapp.config.json

The default config path is ~/.{appname}.config.json (derived from the program name automatically).

--auto_configure

Print the current parameter values (after applying config file and CLI flags) as pretty-printed JSON, then exit. Useful for generating a config file template:

python myscript.py --auto_configure > ~/.myapp.config.json

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Disabling built-in parameters

Pass False for any auto_define_* argument to fargv.parse:

p, _ = fargv.parse(
    {"n": 1},
    auto_define_help=False,
    auto_define_bash_autocomplete=False,
    auto_define_verbosity=False,
    auto_define_config=False,
)

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Legacy API built-in flags

Scripts that still use fargv.fargv (single-dash syntax) get a smaller set of built-in parameters. See Legacy API Reference for details.

Flag	Alias	Description
-help	-h	Print help and exit
-bash_autocomplete	—	Print bash completion script and exit
-v	—	Set verbosity level (integer)