Since https://codeberg.org/a-j-wood/pv/commit/7fcf65e9c3d3b1e3925a9e1a5de64581175896d4, the `$TMPDIR` environment variable is no longer respected. Firstly, this makes `pv` non-conformant to Single Unix Specification's environment variable definition. This seems pretty bad, as using a directory without permission seems like a potential problem. Secondly, this causes `-c` with `-N` to no longer work on systems which have a different `$TMPDIR`, such as [Termux](https://termux.dev/en/). Also, some people might simply not want the app to use `/tmp`. That's why `$TMPDIR` was invented, I guess. There is currently no way to specify a different directory. Yet another reason to use `$TMPDIR` is actually to enable more granular security: someone might want separate directories, with separate permissions, for different applications. If everyone hardcodes `/tmp`, this makes it impossible to separate applications like this. Can you elaborate on how you think using `$TMPDIR` leads to security problems or unpredictable behaviour? Tons of other software use it just fine. IMO actually **not** using it makes `pv` unpredictable, as everyone expects Unix software to respect Unix specifications.