When running the command sed -e “s/a/b/” /tmp/file >/tmp/file While /tmp/file contains data,
why is /tmp/file empty afterwards?

A.
The file order is incorrect. The destination file must be mentioned before the
command to ensure redirection.

B.
The command sed did not match anything in that file therefore the output is empty.

C.
When the shell establishes the redirection it overwrites the target file before the
redirected command starts and opens it for reading.

D.
Redirection for shell commands do not work using the > character. It only works
using the | character instead.