“which in ruby”: Checking if program exists in $PATH from ruby

Question

my scripts rely heavily on external programs and scripts. I need to be sure that a program I need to call exists. Manually, I\'d check this using \'which\' in the commandlin

Answer 1

You can access system environment variables with the ENV hash:

puts ENV['PATH']

It will return the PATH on your system. So if you want to know if program nmap exists, you can do this:

ENV['PATH'].split(':').each {|folder| puts File.exists?(folder+'/nmap')}

This will print true if file was found or false otherwise.