Since Abaqus and CalculiX share mostly the same syntax, the easiest way might be to convert the input file from one solver to run it with the other. You will find some tips for Abaqus → CalculiX conversion here (the other way around, it’s actually easier): A Guide to Modifying Abaqus Input Files for Use in CalculiX - CalculiX (official versions are on www.calculix.de, the official GitHub repository is at https://github.com/Dhondtguido/CalculiX).
Moreover, dev versions of PrePoMax support Abaqus format and even submission too. But CalculiX input files are usually submitted externally in such cases: Using standalone CalculiX
You could also just compare the input decks (at least without the mesh part) - even make a diff in any text editor to find some major differences.