Robust scripts require diligence appropriate for the environment. If you’ve deployed systems with different default tool versions, you factor this in, e.g. by

Robust scripts require diligence appropriate for the environment. If you’ve deployed systems with different default tool versions, you factor this in, e.g. by installing a common version that both can use (or just make scripts that can figure out how to work either way). Two versions of a tool isn’t really any different than two versions of a compiled-in API, except that APIs tend to be more rigid (not always, e.g. some languages allow runtime querying). There’s a common rule in Unix-like systems that essentially says “inputs are liberal, outputs are conservative”. It matters to have programs that can adapt, because this makes a lot of things more practical.