Use wget to detect broken links in a website

while I was updating a website developed using Django, found out that some links were broken due to the change of Django version. To locate all broken links, I used the following commands:

wget --spider -r -l 1 --header='User-Agent: Mozilla/19' -o broken_links.txt http://example.com/updates/

Then I used grep to see whether 404 error was appearing in the output file.

grep -B 2 '404' broken_links.txt
# -B 2 :Print 2 lines of leading context before matching lines which contains the broken link