Rails et al

Except for what little Unix I had in college, I mostly used a Windows laptop until last year when I got a MacBook Pro.

Last week I read Mark Sobell’s excellent “A Practical Guile to UNIX for Mac OS X Users”, playing around with various commands and writing scripts.  I got an appreciation for how much UNIX had affected the design and naming of Java.

I was going to blog about it when I decided to add my picture to my blog, but I could not find it.

My first tool to solve this was using Finder with thumbnails, but  this was not working and was time consuming.

This gave me a real world use case to try and use Linux, which became my second tool.  If I was a master of Linux, I am sure I could have found a single line command to list all the directories that contain a JPEG file.  However, I am not that Linux master so the best I came up with was the following that listed all the full matching paths of any JPEG file:

find . -name *.jpg

The resulting list did not contain only the directories, so I threw together a Ruby script to strip off the file from the path and add it as a key to a hash if the key did not already exist:

s = "not_nil"
dirs = {}

while s != nil do
  s = gets
  if s != nil
    m = s.gsub /\/[^\/]*.jpg$/,''
    dirs[m] = 'value' if !dirs.key? m
  end
end  

dirs.keys.each do |key|
  puts key
end

I then went ahead and piped everything together:

find . -name *.jpg | ruby get_directories.rb | sort | less

This gave me a master list of all the directories I could look over to see if the file was there.

In the end, it didn’t help.  I then remembered the Faces feature in iPhoto, and found it two minutes later.  Turns out that was the right tool for the job.