When "echo" works together with "sha256sum"

By default, echo prints the args and an extra newline("\n"), which is usually not what we need when working with sha256sum.

# echo hello | sha256sum

5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03  -

# echo -n hello | sha256sum

2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824  -