Question

I am running a background rake task. (Using ‘&’). The thing is that I want it to stop sometimes. So I wrote this:

pinger_pid = system "ps | grep rake | awk '{print $1}'"
puts pinger_pid
system "kill -9 #{pinger_pid}"

Seems that I am getting a ‘true’ output garbage! How can I remove that?

output:

ERROR: garbage process ID "true".
Usage:
  kill pid ...              Send SIGTERM to every process listed.
  kill signal pid ...       Send a signal to every process listed.
  kill -s signal pid ...    Send a signal to every process listed.
  kill -l                   List all signal names.
  kill -L                   List all signal names in a nice table.
  kill -l signal            Convert between signal numbers and names.

Answer 1

System returns true or false, depending on the success of the command.

Use %x to capture output:

pinger_pid = %x(ps | grep rake | awk '{print $1}')
puts pinger_pid
system 'kill', '-9', pinger_pid