Module: Command

Defined in:
lib/prick/command.rb

Defined Under Namespace

Classes: Error

Class Method Summary collapse

Class Method Details

.command(cmd, stderr: false, fail: true) ⇒ Object

Execute the shell command ‘cmd’ and return standard output as an array of strings while stderr is passed through unless stderr: is false. If stderr: is true, it returns a tuple of [stdout, stderr] instead. The shell command is executed with the errexit and pipefail bash options

It raises a Command::Error exception if the command fails unless :fail is true. The exit status of the last command is stored in ::status



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# File 'lib/prick/command.rb', line 25

def command(cmd, stderr: false, fail: true)
  cmd = "set -o errexit\nset -o pipefail\n#{cmd}"

  pw = IO::pipe   # pipe[0] for read, pipe[1] for write
  pr = IO::pipe
  pe = IO::pipe

  STDOUT.flush

  pid = fork {
    pw[1].close
    pr[0].close
    pe[0].close

    STDIN.reopen(pw[0])
    pw[0].close

    STDOUT.reopen(pr[1])
    pr[1].close

    STDERR.reopen(pe[1])
    pe[1].close

    exec(cmd)
  }

  pw[0].close
  pr[1].close
  pe[1].close

  @status = Process.waitpid2(pid)[1].exitstatus

  out = pr[0].readlines.collect { |line| line.chop }
  err = pe[0].readlines.collect { |line| line.chop }

  pw[1].close
  pr[0].close
  pe[0].close

  result = 
      case stderr
        when true; [out, err]
        when false; out
        when NilClass; $stderr.puts err
      else
        raise Internal, "Unexpected value for :stderr - #{stderr.inspect}"
      end

  if @status == 0 || fail == false
    result
  elsif fail
    raise Command::Error.new("\n" + cmd + "\n" + (out + err).join("\n") + "\n", status, out, err)
  end
end

.command?(cmd, expect: 0) ⇒ Boolean

Like command but returns true if the command exited with the expected status

Returns:

  • (Boolean) 


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# File 'lib/prick/command.rb', line 84

def command?(cmd, expect: 0)
  command(cmd, fail: false)
  @status == expect
end

.status ⇒ Object

Exit status of the last command



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# File 'lib/prick/command.rb', line 81

def status() @status end