Ruby net/ssh is not running bash commands in background-CodePudding

I am having a hard time running bash commands in background from a Ruby script.

For this question, I am using a simplified example.

This is how commands are working as expected when I run them from PuTTY.

running basch commands in background (click to see the picture, because StackOverlow is not allowing me to show pictures yet)

Now, I try to replicate this from Ruby, using this little script shown below:

ruby script (click to see the picture, because StackOverlow is not allowing me to show pictures yet)

This is the outout I get when I run such a Ruby script:

script output (click to see the picture, because StackOverlow is not allowing me to show pictures yet)

For your analysis, here is the transcription of the Ruby script:

require 'net/ssh'
net_remote_ip = '74.****122'
ssh_username = 'bots'
ssh_password = 'San*****'
get_ssh_port = '22'
ssh = Net::SSH.start(net_remote_ip, ssh_username, :password => ssh_password, :port => get_ssh_port)
s = "bash --login -c 'sleep 600' &"
print "run (#{s})... "
stdout = ssh.exec!(s)
puts "done (#{stdout.strip})"
ssh.close
exit(0)

CodePudding user response：

You need to redirect both stdout and stderr somewhere else than the terminal, otherwise exec! will hang waiting for process output.

This is the simplest solution I found:

ssh.exec!("sleep 600 &> /dev/null &")

&> redirects both stdin and stderr at the same time. If you want to redirect the output for logging, you can do so separately if you like:

ssh.exec!("command 2> error.log > output.log &")