I use the 2Apr2025 version lammps.
According to this page fix bond/react command — LAMMPS documentation I can use “file“ as a common_keyword. However I got this error.
fix r1 all bond/react file react.json stabilization yes nvt_grp .05 react R1 all 1 1.5 2 pre_1 post_1 map_1.simple prob 0.8 10101
I have not used this fix personally, but I checked this page in the stable release (which is 22Jul2025) fix bond/react command — LAMMPS documentation and it does not have the file keyword. And your version is even older than that. So that explains it I think.
btw, in the latest documentation it says
common_keyword = stabilization or reset_mol_ids or rate_limit or max_rxn
but the box below also includes shuffle_seed and file which are not listed in the line above. I don’t know why.
This is an oversight that sometimes happen during documentation updates. It will be corrected ASAP.
This LAMMPS version is too old for having this feature. You are looking at the (feature release) online documentation which always reflects the latest feature release. You need to look at the documentation from the LAMMPS version you are using. This is included in the LAMMPS source code packages (in both HTML and PDF format).