def write_crontab(contents)
tmp_cron_file = Tempfile.new('whenever_tmp_cron').path
File.open(tmp_cron_file, File::WRONLY | File::APPEND) do |file|
file << contents
end
command = ['crontab']
command << "-u #{@options[:user]}" if @options[:user]
command << tmp_cron_file
if system(command.join(' '))
action = 'written' if @options[:write]
action = 'updated' if @options[:update]
puts "[write] crontab file #{action}"
exit(0)
else
warn "[fail] Couldn't write crontab; try running `whenever' with no options to ensure your schedule file is valid."
exit(1)
end
end