Select Code to Download

$ perl -MO=Deparse -e 's/s/http://example.com/[404 Not Found]/g'
Bareword found where operator expected at -e line 1, near "404 Not"
    (Missing operator before Not?)
syntax error at -e line 1, near "404 Not Found"
-e had compilation errors.

$ perl -MO=Deparse -e 's/http://example.com/[404 Not Found]/g'
Bareword found where operator expected at -e line 1, near "404 Not"
...
Regexp modifiers "/a" and "/l" are mutually exclusive at -e line 1, at
+ end of line
syntax error at -e line 1, near "404 Not Found"
-e had compilation errors.

$ perl -MO=Deparse -e 's{http://example.com}{[404 Not Found]}g'
s[http://example.com][[404 Not Found]]g;
-e syntax OK

#!/usr/bin/env perl -l

...
>http://bad3.com/</a>
<a href="http://bad4.com/">http://bad3.com/</a>
<a href="http://bad4.com/">http://bad4.com/</a>

*** ORIGINAL ***
<h1>HTM1</h1>
...
<span class="bad-url">[404 Not Found]</span>
<a href="http://bad4.com/">http://bad3.com/</a>
<span class="bad-url">[404 Not Found]</span>