# Installing your own version of CESM

These instructions are for users who need to download their own version of CESM2.

{% hint style="warning" %}
Do not load the CESM module. If you have a cesm module loaded, unload it:

`module unload cesm`
{% endhint %}

Clone the version of CESM you want from the github repo:

```bash
git clone -b release-cesm2.2.0 https://github.com/ESCOMP/CESM.git my_cesm_sandbox
cd my_cesm_sandbox
./manage_externals/checkout_externals
```

The various Oscar-specific XML files needed to run CESM, including

* config\_batch.xml
* config\_compilers.xml
* config\_machines.xml

can be obtained from [this github repo](https://github.com/brown-ccv/CIME_Oscar). The easiest way to incorporate these files into your build is to place them in a directory named .cime within your home directory (i.e., \~/.cime). For example:

```bash
git clone https://github.com/brown-ccv/CIME_Oscar ~/.cime
```

To setup, build, and run a case on Oscar:

1. Load the necessary modules (line 1-7 below)
2. Move to the cime\_scripts directory (line 8)
3. Create a new case, selecting your desired \<CASENAME>, \<COMPSET>, and \<GRID > (line 9)
4. Move to your CASEROOT directory (line 10)
5. Setup the case (line 11)
6. Build the case (line 12)
7. Submit the case (line 13)

```bash
module load netcdf/4.9.0_intel_2020.2_hdf5_1.12.2_slurm22 \
            hdf5/1.12.2_openmpi_4.0.7_intel_2020.2_slurm22 \
            mpi/openmpi_4.0.7_intel_2020.2_slurm22 \
            perl/5.36.0 \
            intel/2020.2 \
            blas/3.7.0 \
            lapack/3.7.0
cd my_cesm_sandbox/cime/scripts
./create_newcase --mach oscar --case <CASENAME> --compset <COMPSET> --res <GRID>
cd <CASENAME>
./case.setup
./case.build
./case.submit
```

By default, component log files, history files, and restart files for your case will be placed in /oscar/home/$USER/data/$USER/archive/\<CASENAME>.