docs: Add note about --fs swallowing non-option arguments.

Includes suggestions of how to use `--fs` commands with firmware files and
devices.

Closes: #6

Author: glenn20

README.md

@@ -1,7 +1,23 @@
 # mp-image-tool-esp32: Working with esp32 firmware files and devices
 
-![CI Tests](https://github.com/glenn20/mp-image-tool-esp32/actions/workflows/ci-tests.yaml/badge.svg)
-![CI Tests](https://github.com/glenn20/mp-image-tool-esp32/actions/workflows/ci-release.yaml/badge.svg)
+[![PyPI](
+  https://img.shields.io/pypi/v/mp-image-tool-esp32)](
+  https://pypi.org/project/mp-image-tool-esp32)
+[![PyPI Supported Python Versions](
+  https://img.shields.io/pypi/pyversions/mp-image-tool-esp32.svg)](
+  https://pypi.python.org/pypi/mp-image-tool-esp32/)
+[![GitHub Actions (Tests)](
+  https://github.com/glenn20/mp-image-tool-esp32/actions/workflows/ci-tests.yaml/badge.svg)](
+  https://github.com/glenn20/mp-image-tool-esp32/actions/workflows/ci-tests.yaml)
+[![GitHub Actions (Publish)](
+  https://github.com/glenn20/mp-image-tool-esp32/actions/workflows/ci-release.yaml/badge.svg)](
+  https://github.com/glenn20/mp-image-tool-esp32/actions/workflows/ci-release.yaml)
+[![PyPI - License](
+  https://img.shields.io/pypi/l/mp-image-tool-esp32)](
+  https://opensource.org/licenses/MIT)
+[![pre-commit](
+  https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit)](
+  https://github.com/pre-commit/pre-commit)
 
 Tool for manipulating partition tables and files in MicroPython esp32 firmware
 image files and device flash storage.
@@ -292,6 +308,12 @@ Eg. `mp-image-tool-esp32 a0 --fs mkfs vfs --fs put ./rootfs/* /` will create
 a new littlefs filesystem on the 'vfs' partition and initialise it with the
 files from `./rootfs/` on the local computer.
 
+`--fs` commands will swallow any non-option arguments following, so use `--` to
+separate them if needed, eg:
+
+- `mp-image-tool-esp32 --fs ls /lib /bin -- firmware.bin` or
+- `mp-image-tool-esp32 firmware.bin --fs ls /lib /bin`.
+
 You can also use [`littlefs-python`](https://github.com/jrast/littlefs-python)
 to build filesystem partitions on your computer and flash them to the device,
 eg:

src/mp_image_tool_esp32/main.py

@@ -155,7 +155,8 @@ class TypedNamespace(argparse.Namespace):
     K=kilobytes, B=blocks (0x1000=4096 bytes)).
 
     --fs commands include: ls, get, put, mkdir, rm, rename, cat, info, mkfs,
-    df, grow and more.
+    df, grow and more. --fs will swallow any non-option arguments following, so
+    use `--` to separate them if needed, eg `--fs ls /lib /bin -- firmware.bin`.
 
     Options --erase-fs and --ota-update can only be used when operating on
     serial-attached devices (not firmware files).