How to wait for system command to end

Question

I\'m converting an XLS 2 CSV file with a system command in Ruby.

After the conversion I\'m processing the CSV files, but the conversion is still running when the progr

Answer 1

Ruby's system("...") method is synchronous; i.e. it waits for the command it calls to return an exit code and system returns true if the command exited with a 0 status and false if it exited with a non-0 status. Ruby's backticks return the output of the commmand:

a = `ls`

will set a to a string with a listing of the current working directory.

So it appears that xls2csv.exe is returning an exit code before it finishes what it's supposed to do. Maybe this is a Windows issue. So it looks like you're going to have to loop until the file exists:

until File.exist?("file1.csv")
  sleep 1
end

Answer 2

Try to use threads:

command = Thread.new do
  system('ruby programm.rb') # long-long programm
end
command.join                 # main programm waiting for thread
puts "command complete"