$ echo -n "https://twtxt.net/user/prologic/twtxt.txt\n2020-07-18T12:39:52Z\nHello World! 😊" | sha1sum | head -c 11
87fd9b0ae4e
$ echo -n "https://twtxt.net/user/prologic/twtxt.txt\n2020-07-18T12:39:52Z\nHello World! 😊" | sha1sum | head -c 11
87fd9b0ae4e
"
, and other "spurious" characters in it?
echo
with something like pbpaste
or similar. You'd just need to shell escape things like "
and such. That's all. Alternatives you can shove the 3 lines into a small file and cat file.txt | ...
echo
with something like pbpaste
or similar. You'd just need to shell escape things like "
and such. That's all. Alternatives you can shove the 3 lines into a small file and cat file.txt | ...

git only uses sha1 because they're stuck with it: migrating is very hard. There was an effort to move git to sha256 but I don't know its status. I think there is progress being made with Game Of Trees, a git clone that uses the same on-disk format.
I can't imagine any benefit to using sha1, except that maybe some very old software might support sha1 but not sha256.