My findings so far: setting User-Agent to that new string and executing a .cgi script complains about: syntax error near unexpected token `newline' in `#!/bin/b

My findings so far: setting User-Agent to that new string and executing a .cgi script complains about: syntax error near unexpected token `newline' in `#!/bin/bash'. (My speculation is that we are in some kind of parsing context where no newlines are expected; none are given on the example bash -c ... line, but when you actually run a script there will be a newline). I tried to change this to a Python script and instead use os.popen. Well, Ubuntu /bin/sh is "dash" so that's not affected. I tried to explicitly call bash via os.popen("bash -c 'some command'") -- no go either, as that bash command started by parsing some /etc/bash.bashrc file and complaining about newlines there. Finally I used os.popen("bash --norc -c '/tmp/file date'") -- and that ended up running "date > /tmp/file" from the CGI script. I tried replacing /bin/sh by "bash" instead of dash. That now made the CGI script choke on reading some other RC files due to the unexpected newlines in the context bash starts with. So the question from me still seems to be: what is the weird context setup by that environment setup, and what else can do you with it than to redirect $1 to $0 ?