[stouset]

https://man7.org/linux/man-pages/man1/mkfifo.1.html

Pretty simple. This creates a named pipe. One end of a shell command redirects to it, one end redirects from it. rm when finished.

[akdev1l]

You can just use process substitution

cat <(secret-print my-secret)

[SoftTalker]

In a shell script situation, you'd typically trap EXIT and ERR and remove the fifo in the handler.