fix piping of redirected stdout

e.g.
Assume you have a script that print to stdout as well as stderr:
[test.lua]
print("foo")
io.stderr:write("bar")

Then run this script, redirecting [2] to stdout, and [1] to dev null, then piping to grep

./test.lua 2>&1 >/dev/null | grep baz

This test should print NOTHING to the terminal, "foo" went to dev null, "bar" when to stdout, and grep matched on "baz", thus should not print. But the bug I found was that [2] was redirected to terminal tty stdout and then AFTER that the piping code added a pipe on [1], but [2] was already pointing to tty. The fix is to move the piping before redirections are created, so that when [2] redirects to stdout, stdout is already the pipe.

src/main/resources/assets/opencomputers/loot/openos/lib/sh.lua

@@ -252,27 +252,32 @@ function sh.internal.createThreads(commands, eargs, env)
 
     threads[i] = thread
 
-    if thread then
+    if not thread then
-      -- smart check if ios should be loaded
-      if tx.first(args, function(token) return token == "<" or token:find(">") end) then
-        args, reason = sh.internal.buildCommandRedirects(thread, args)
-      end
-    end
-    
-    if not args or not thread then
       for i,t in ipairs(threads) do
         process.internal.close(t)
       end
       return nil, reason
     end
 
-    process.info(thread).data.args = tx.concat(args, eargs or {})
+    process.info(thread).data.args = args
   end
 
   if #threads > 1 then
     sh.internal.buildPipeChain(threads)
   end
 
+  for i = 1, #threads do
+    local thread = threads[i]
+    local args = process.info(thread).data.args
+
+    -- smart check if ios should be loaded
+    if tx.first(args, function(token) return token == "<" or token:find(">") end) then
+      args, reason = sh.internal.buildCommandRedirects(thread, args)
+    end
+
+    process.info(thread).data.args = tx.concat(args, eargs or {})
+  end
+
   return threads
 end