Ghostscript check, sends e-mail if one occurs

Question

I've created a program that will search our work server where Ghostscripts occur. How it accomplishes this is by first sshing to the server specified, running a bash command to search the server for Ghostscripts caused by our guy that uses them, most frequently. If it finds one, it e-mails somebody on my team. It will also e-mail if it doesn't find one.

I'm curious to know if there are other ways I can do this specific task. Better syntax, etc..

#!/local/usr/bin/ruby
require 'rubygems'
require '<mailgem>'
require 'etc'
require 'net/ssh'
class GhostScript
 attr_accessor :host, :usr, :pass
 def initialize(host, usr, pass)
 @host = host
 @usr = usr
 @pass = pass
 end
 def script_search
 ssh = Net::SSH.start(host, usr, :password => pass)
 res = ssh.exec!('ps -u <user>|grep gs')
 if res == nil
 MailGem::Mail.new do |m|
 m.to = '<email-address>'
 m.subject = 'GhostScript not found'
 m.body = "GS not found on server: #{host}"
 end.send
 else
 alert(res)
 end
 end
 def alert(res)
 MailGem::Mail.new do |m|
 m.to = '<email-address>'
 m.subject = 'GhostScript found'
 m.body = "GS script found on server: #{host}",
 "Results of search: #{res}"
 end.send
 end
end
check = GhostScript.new('<server>', Etc.getlogin, nil)
check.script_search

• Spike: Isn't res always a (possibly empty) string?
• Bam: @Spike I've had this conversation with someone once before, it runs a bash command and either returns nil, an empty string, or the command. For some reason nil always works for me, so I just use it because it's easy.

Answer 1

Looks pretty good, just some minor details:

• if res == nil -> if !res

• DRY the sending of the email by creating a new method: send_email(to, subject, body)

• Subjective: I'd not include a blank lines when there is a change of indentation level (between class and attr_accesor)

• Bam: I just think the space makes it look a little bit neater. I'm confused as to what this would do exactly !res, does it do the same thing as the == nil just shorter? Also, the method is a good idea, I'll work that in somehow.
• tokland: 1) The rationale for not adding this blank line is consistency: why do you add there and not between def initialize(host, usr, pass) and @host = host, for exemple? 2) if !res translates to if res == nil || res == false, which is not exactly what you had, but probably it works all the same. It's more idiomatic (because it's more declarative).