Debugging.md

@@ -13,3 +13,11 @@ CC='mpicc'
 +ICON_FCFLAGS='-O2 -assume realloc_lhs -ftz -DDO_NOT_COMBINE_PUT_AND_NOCHECK'
 +ICON_OCEAN_FCFLAGS='-O3 -assume norealloc_lhs -reentrancy threaded -qopt-report-file=stdout -qopt-report=0 -qopt-report-phase=vec'
 ```
+
+## Start DDT from a login-shell with X forwarding
+
+```bash
+ssh -X username@mistral.dkrz.de
+module load arm-forge
+ddt &
+```
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