Create README.md

README.md

@@ -0,0 +1,82 @@
+# UMfile_utils
+
+UMfile_util is a Python library that provides specific tools to process [UM files](https://code.metoffice.gov.uk/doc/um/latest/papers/umdp_F03.pdf).
+
+## List of functions
+
+- [perturbIC](#perturbic)
+- [um_fields_subset](#um-fields-subset)
+- [change_date](#change-date)
+
+### perturbIC.py 
+The `perturbIC` function applies a random perturbation to a restart file, with an optional seed to control the random generation. 
+This can be useful for simulations that fail due to random divergence or for generating multiple ensemble members in climate experiments.
+
+Run `pertubIC --help` for detailed usage information.
+
+### um_fields_subset.py
+
+This code runs on a Dump file and allows the user to select a group of fields in the file to store  in a new fields file or exclude a 
+group of fields from the file. Both of these functionalities will create a new output file. 
+
+
+### change_date.py
+This code runs on any UM field file. It allows the user to change the timestamps (metadata) of a restart dump file, without modifying 
+its data content. It changes the initial and valid date of the header and the header date of each field in the file.
+
+
+Currently these programs include a work around to deal with the river field grids and need to be run without the mule validation. 
+This is defualt to the programs. The validation can be included using --validate
+
+## Installation
+
+
+## Usage
+### perturbIC.py 
+
+If the user wants to run perturbIC with a specific output filename
+```python
+python perturbIC input_file_path -a 0.01 -s 2234 -o output_file_path
+```
+Otherwise it is optional perturbIC will create a filename from the input path
+```python
+python perturbIC input_file_path -a 0.01 -s 2234
+```
+
+The amplitude and seed are also optional as well
+```python
+python perturbIC input_file_path -a 0.01 -s 2234
+```
+### um_fields_subset.py
+
+To take a subset of field the user must provide a either a list of fields to exculde (-x)
+```python
+python um_fields_subset.py input_file_path -x 155,156,3100,3101
+```
+
+To take a subset of field the user must provide a either a list of fields to include (-v)
+```python
+python um_fields_subset.py input_file_path -v 155,156,3100,3101
+```
+
+Or you can choose to have the program to only include pronostics -p
+```python
+python um_fields_subset.py input_file_path -p
+```
+These three options must be run seperately
+
+### change_dump_date.py
+User can either enter in a year, month, and day seperately (-y -m -d),
+```python
+python change_dump_date.py input_file_path -y 2025 -m 1 -d 22
+```
+or the user can enter in a date in the format of YYYYMMDD.
+```python
+python change_dump_date.py input_file_path -date 20250122
+```
+## Contributing
+TO BE ADDED
+
+
+## License
+TO BE ADDED