prefixing of each line of output

examples/eg_helper.rb

@@ -3,7 +3,7 @@
 require 'exemplor'
 require 'angry_hash'
 
-root = Pathname(__FILE__).dirname.parent
+root = Pathname('../..').expand_path(__FILE__)
 
 $LOAD_PATH << root+'examples'
 $LOAD_PATH << root+'lib'

examples/shell.eg.rb

@@ -0,0 +1,12 @@
+require 'eg_helper'
+
+eg.helpers do
+  include CommonMob::ShellHelper
+end
+
+eg 'shelly' do
+  cmd = "echo hello; echo mars >&2; echo world"
+  Show( sh(cmd                                                ).execute )
+  Show( sh(cmd, :prefix => "[OXX]"                            ).execute )                       
+  Show( sh(cmd, :prefix => {:err => "[OXX]", :out => "[MXX]"} ).execute )
+end

lib/common_mob/shell.rb

@@ -39,15 +39,27 @@ def initialize(*args,&block)
     def execute
       error,out = nil,nil
 
+      # XXX interleave out and err
       rv = popen4(options) {|pid,stdin,stdout,stderr|
         out   = stdout.read
         error = stderr.read
       }
 
-      # TODO print as debug
+      if prefix = options[:prefix]
+        if Hash === prefix
+          pre_err = prefix[:err]
+          pre_out = prefix[:out]
+        else
+          pre_err = prefix
+          pre_out = prefix
+        end
 
-      rv.stderr = error
-      rv.stdout = out
+        rv.stderr = error.gsub(/^(.*)$/, "#{pre_err}\\1")
+        rv.stdout = out.gsub(/^(.*)$/  , "#{pre_out}\\1")
+      else
+        rv.stderr = error
+        rv.stdout = out
+      end
 
       rv
     end
@@ -76,7 +88,7 @@ def ok?
 
       def ensure_ok!
         unless ok?
-          ex = ShellError.new("unable to run options=#{options.inspect}\noutput=#{stdout}\nerror=#{stderr}")
+          ex = ShellError.new("unable to run\noptions=#{options.pretty_inspect}\noutput=#{stdout}\nerror=#{stderr}")
           ex.result = self
           raise(ex)
         end