Pipe one shell command into another

[Andrew via Digitalmars-d-learn]

Hi,

I'd like to run a shell command which involves piping one thing 
into another and then processes the output line by line, i.e. 
something like "ls -l | sort -k5,5n"

What I've come up so far with is:

import std.process;
import std.stdio;

void main(){
  auto pipesLs = pipeProcess(["ls", "-l"], Redirect.stdout);
  auto pipesSort = pipeProcess(["sort", "-k5,5n"], Redirect.all);

  scope (exit) wait(pipesSort.pid);

  foreach(line; pipesLs.stdout.byLine)
    pipesSort.stdin.writeln(line);

  pipesSort.stdin.close;

  foreach(line; pipesSort.stdout.byLine)
    writeln(line);
}

This seems to work on this simple example, but is there a better 
way to do it, and if not, is this reliable? Also, could someone 
explain to me the necessity of the wait command?

Thanks very much

Andrew