Note: BTRFS defrag will result in a different copy at the end of the day. If you’re using snapshots this will lead to increased utilization.

Out of curiosity, how?

< urls.txt while read -r url; ...

Is a syntax error.

while read -r url < urls.txt; ...

Result in an infinite loop.

You can also avoid cat since you aren’t actually concatenating files (depending on file size this can be much faster):

while read -r url; do echo "download $url"; done < urls.txt

I suppose I could have phrased that better. The registers themselves correspond to particular applications/stages, but the values store in those registers should change based on how the application/stage was loaded. Switch the order or inject a new binary and the hash from that stage on should change.

Any changes in the boot process should change various PCR registers. https://wiki.archlinux.org/title/Trusted_Platform_Module#Accessing_PCR_registers