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.

Question

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.

Quizplus · Accepted Answer

When the shell processes the command, it first opens the file for writing (which clears the file) before executing the `sed` command, resulting in an empty file.

When Running the Command Sed -E "S/a/b/" /Tmp/file >/Tmp/file While