add ProcessEachLine

gistfile1.diff

diff --git a/base/process.jl b/base/process.jl
index e8fadae..74a8914 100644
--- a/base/process.jl
+++ b/base/process.jl
@@ -677,11 +677,27 @@ end
 readall(ports::Ports) = _readall(ports, cmds(ports))
 readall(cmds::Cmds)   = _readall(stdout(cmds), cmds)
 
+type ProcessEachLine
+    stream::IO
+    c::Cmds
+end
+
+start(itr::ProcessEachLine) = readline(itr.stream)
+function done(itr::ProcessEachLine, line)
+    if !isempty(line)
+        return false
+    end
+    wait(itr.c)
+    close(itr.stream)
+    true
+end
+next(itr::ProcessEachLine, this_line) = (this_line, readline(itr.stream))
+
 function _each_line(ports::Ports, cmds::Cmds)
     r = read_from(ports)
     spawn(cmds)
     fh = fdio(r.fd, true)
-    EachLine(fh)
+    ProcessEachLine(fh, cmds)
 end
 
 each_line(ports::Ports) = _each_line(ports, cmds(ports))