>> `ls -l "/usr/local/etc/git-completion.bash"`
=> "-rwxrwxr-x  1 root  admin  44883 11 Oct  2009 /usr/local/etc/git-completion.bash\n"

>> `whoami`
=> "ben\n"
>> `groups ben`.split(' ').include? 'admin'
=> true

>> File.writable? "/usr/local/etc/git-completion.bash"
=> false
>> File.writable_real? "/usr/local/etc/git-completion.bash"
=> true

>> File.open("/usr/local/etc/git-completion.bash", "a") { puts "opened for writing OK" }
opened for writing OK
=> nil


>> `uname -a`
=> "Darwin hat.local 10.3.0 Darwin Kernel Version 10.3.0: Fri Feb 26 11:58:09 PST 2010; root:xnu-1504.3.12~1/RELEASE_I386 i386\n"