ithinkihaveacat's questions

Why do the DNS records authoritative name servers frequently give different results than cached name servers if "ANY" records are requested?

The authoritative name servers seem to consistently provide more records than the cache--for example returning MX or TXT records when the caching name server will only return these records if they are explicitly requested.

For example, on my home (OS X) system, the difference between the following two commands

$ dig -t ANY +noall +nottl +answer microsoft.com
$ dig -t ANY +noall +nottl +answer microsoft.com @ns1.msft.net

is that the first only returns the NS records; the second adds in MX, SOA and TXT. However on a separate Linux system, with a completely different DNS setup, the only records "missing" are MX and SOA.

In OS X, how can I dereference a symbolic link to a canonical file name? (i.e. one starting with /.)

That is, I'm after the equivalent of GNU readlink's -f option:

kapow:~$ greadlink -f .bash_profile
/Users/mjs/.config/home/.bash_profile

OS X's readlink instead returns a relative link:

kapow:~$ readlink .bash_profile
.config/home/.bash_profile

stat(1) does have an amazing number of options, but I couldn't figure out the right combination to do what I want.

On RedHat/CentOS systems, all of the service management scripts in /etc/init.d (and also run by the "service" command) produce color output. (i.e. the "[ OK ]" and "[FAILED]" strings.) How do I disable this? (The color-producing escape sequences are making the webistrano output more ugly than it needs to be.)

Is it possible to configure Apache for different virtual hosts based on the source IP? (i.e. same interface, same hostname, but two different virtual hosts, with different content, based on source IP.)

The motivation for this is so that my IP address can access the site proper, but that everyone else gets the holding page. The conventional solution seems to be to use mod_rewrite to direct visitors to a separate page within the same docroot, but I'd like to use a completely different docroot for the holding page instead.

Apache's DirectoryIndex directive tells Apache to look for, e.g. index.html and index.php if the client requests a directory.

Is there some easy way to get Apache to analogously look for e.g. /$filename.jpg if the client requests /$filename?

For example, if the client requested /foo, then Apache might be configure to look for /foo.jpg and /foo.png on disk, and return a 404 if neither of these files exist. (I am aware that it's possible to use mod_rewrite for this, however I would like a simple (and more performant) solution.)

Is it possible to get logrotate to consider logfiles in a directory and all its subdirectories? (i.e. without explicitly listing the subdirectories.)

mysqladmin -uroot create foo returns an exit status of 1 if foo exists, and 0 otherwise, but of course it will also create the database if it doesn't already exist. Is there some easy way to simply check whether a database exists?

Both Interix and Cygwin appear to provide a Unix-like user environment in Windows. What are the practical differences between the two, in terms of, for example:

• Unix-like "feel"
• Performance
• Package availability/ease in compiling random software downloaded from the internet
• Integration with Windows applications and tools
• Integration/compatibility with virtual machines (e.g. is it possible for Interix and an Ubuntu virtual machine to share the same "home directory")
• Size of user base/level of community support

One difference I am aware of is that Interix requires Windows 7 Enterprise or Ultimate edition; Cygwin will run on anything.