Bio::Commandeer provides a dead simple method of running shell commands from within Ruby:
require 'bio-commandeer' Bio::Commandeer.run 'echo 5' #=> "5\n"
The real advantage of bio-commandeer is that when something goes wrong, it tells you; you don't have go looking for the error. Take for instance this simple script:
#!/usr/bin/env ruby require 'bio-commandeer' print Bio::Commandeer.run('echo 5') print Bio::Commandeer.run('cat /not_a_file')
The output is:
5 <snip>/lib/bio-commandeer/commandeer.rb:32:in `run': Command returned non-zero exit status (1), likely indicating failure. Command run was cat /not_a_file and the STDERR was: (Bio::CommandFailedException) cat: /not_a_file: No such file or directory from spec/eg.rb:4:in `<main>'
When a command fails (as detected through a non-zero exit status), then a
Bio::CommandFailedException exception is thrown. While you can catch these exceptions with begin/rescue, often the best to do is fail, especially if you are writing quick one-off scripts.
Of course, when running commands such as this, take care not to trust the input directly from the command line, and especially not from a website. When in doubt, use
inspect around the arguments to make sure that you don't run into little bobby tables.
Note: this software is under active development! Currently it is perhaps overly opinionated and as such not overly flexible.
Commands run are logged with level info, if requested:
require 'bio-commandeer' Bio::Log::CLI.logger("stderr"); Bio::Log::CLI.trace("info"); puts Bio::Commandeer.run 'echo 5', :log=>true
On stderr this gives
INFO bio-commandeer: Running command: echo 5 INFO bio-commandeer: Command finished with exitstatus 0
Or a logging can be given directly, so long as it has an
Bio::Commandeer.run 'echo 5', :log=>my_logger
A command can also be run to completion without raising an errors using
require 'bio-commandeer' result = Bio::Commandeer.run_to_finish 'echo 5' #=> Bio::CommandResult result.stdout #=> "5\n"
gem install bio-commandeer
This Biogem is published at (http://biogems.info/index.html#bio-commandeer)
Copyright (c) 2014-2015 Ben J. Woodcroft. See LICENSE.txt for further details.