Question

Im trying to do this:

current_size = exec("ps -o rss $(pgrep rake)")

When it runs, I get:

RSS
2784
560
568
788

but the process exits.

Any idea what im doing wrong?

I also tried:

 exec("ps -o rss #{Process.pid}")

Same problem

Answer 1

From “ri Kernel.exec”

Replaces the current process by running the given external _command_

Your process has been replaced by the ps process which prints out the data and then exits.

You probably want Kernel.`

 Returns the standard output of running _cmd_ in a subshell. The
 built-in syntax +%x{...}+ uses this method. Sets +$?+ to the
 process status.

Using %x{ } seems like the better option.

current_size = %x{ ps -o rss $(pgrep rake) }