Debugging.md

@@ -12,4 +12,12 @@ CC='mpicc'
 +FCFLAGS="-I${NETCDFF_ROOT}/include -gdwarf-4 -g -march=native -pc64 -fp-model source"
 +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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