A systems administrator needs to append output of command to the contents of ls -lha /opt a test.txt file. Which of the following commands will accomplish this?

The single > operator redirects output to a file but overwrites all existing contents rather than appending.

The < operator redirects a file as standard input to a command, not output from a command to a file.

The >> operator appends standard output to an existing file without overwriting its contents. Running ls -lha /opt >> test.txt will add the directory listing to the end of test.txt, preserving any data already in the file.

The << operator is a here-document delimiter that reads input inline from the shell script itself, not a file append mechanism.