User-agent: *
Disallow: *.pdf$  # Block pdf files from all bots. Albeit non-standard, it works for major search engines.

Disallow: *.docx$  # Block docx files from all bots. Albeit non-standard, it works for major search engines.
Disallow: *.doc$  # Block doc files from all bots. Albeit non-standard, it works for major search engines.

Disallow: *.pptx$  # Block pptx files from all bots. Albeit non-standard, it works for major search engines.
Disallow: *.ppt$  # Block ppt files from all bots. Albeit non-standard, it works for major search engines.

Disallow: *.xlsx$  # Block xlsx files from all bots. Albeit non-standard, it works for major search engines.
Disallow: *.xls$  # Block xls files from all bots. Albeit non-standard, it works for major search engines.

Disallow: /courses/