Ruby

Run a system command (shell command) and know whether it failed

if you don’t need to pass STDIN to the command

if you don’t care about output: system
- if you are passing arguments to the command
  - ```
  system('rm', '-r', directory) or raise "Failed to remove #{directory}"
```
- if you have more complicated error handling
  - command_successful = system('rm', '-r', directory) unless command_successful # complicated error handling end
- if you aren’t passing any arguments to the command
  - ```
  system(["ls", "ls"])
```
- This is better than system("ls"), which tells the shell to run ls instead of running ls directly.
- The return value of system is true if the command ran successfully and falsey if it ran unsuccessfully or failed to run.

if you want to capture STDOUT: Open3.capture2

require 'open3'

stdout, status = Open3.capture2('diskutil', 'info', 'disk0')
unless status.success?
  raise "the command failed"
end

puts stdout

if you want to capture STDOUT and STDERR: Open3.capture3

require 'open3'

stdout, stderr, status = Open3.capture3('example', '--arg')
unless status.success?
  raise "the command failed"
end

puts stdout
$stderr.puts stderr

if you do need to pass STDIN to the command
- I didn’t research this in detail yet, but I bet the solution is the Open3 standard library again, and its methods like popen2.

roryokane/README.md

Ruby

Run a system command (shell command) and know whether it failed