Simon Tatham on Nostr: for that I use a tiny utility I wrote called 'reservoir', which reads and buffers ...

for that I use a tiny utility I wrote called 'reservoir', which reads and buffers input until EOF, then writes it all out again. With the -o option, you can tell it a file to overwrite. So you can do this kind of thing, without depending on your filter tool having an option that works like sed -i:

$arbitrary_filtering_command < filename | reservoir -o filename

https://www.chiark.greenend.org.uk/~sgtatham/utils/
https://www.chiark.greenend.org.uk/~sgtatham/utils/reservoir.html