Extract body of child process to a method
Reduce effective scope of pipe variables
Promote log stream to a local
Log directly to the log file in non-verbose mode
Don't pass the read end of the pipe to exec_cmd
Skip allocating a pipe entirely in non-verbose mode
Reduce branches and effective scope of some variables
Cache result of ARGV.verbose? on the stack
Flush log stream before exec
Ensure log file is closed
Remove debugging code :shame:
Less code in begin block
Remove 1.9 dependency from package

The 1.9 dependency breaks the selecta package when installing on Mac computers.
selecta: add 0.0.3 bottle.