From Andreas:

I have updated the Alien README file. The one you ship is very old and not
correct anymore.


git-svn-id: http://root.cern.ch/svn/root/trunk@13702 27541ba8-7e3a-0410-8455-c3a389f83636

README/README.ALIEN

-=========================================================================
-How to use the TGrid/TAlien class V1.0 - Andreas.Peters@cern.ch
-=========================================================================
-
-To connect to Alien you have to connect to a running API service or you
-let the system start an API server on your local machine, if you have a
-full AliEn client installation.
-
-Creating <gGrid> instance:
-1.  // connecting to an API service on the local machine
-    // if there is already one running, it is reused!
-
-    TGrid::Connect("alien://localhost");
-    or
-    TGrid::Connect("alien://");
-
-2.  // connecting to an already running API server
-    TGrid::Connect("alien://<host>:<port>/#?direct");
-
-3.  // asking the factory service to startup an API on a service machine
-    // (currently not working)
-    TGrid::Connect("alien://<factoryhost>:<factoryport>");
-
-If you have executed TGrid::Connect(), the gGrid global variable
-should be set != 0.
-
-Examples of gGrid usage:
-
-1) List directories of the catalogue:
-
-   int handle = gGrid->OpenDir("<aliendir>");
-   TGridResult *gr = gGrid->CreateGridResult(handle);
-   gr->Print();
-   delete gr;
-
-2) Find all files under a directory:
-
-   int handle = gGrid->Find("<aliendir>","*","");
-   TGridResult *gr = gGrid->CreateGridResult(handle);
-   gr->Print();
-   delete gr;
-
-3) Inserting Files in the catalogue
-
-   if (!gGrid) {
-      TGrid::Connect("alien://aliens7.cern.ch:15000/?direct","");
-   }
-
-   TString dirname("/alice_mdc/user/a/alimdc/testdir");
-
-   if ((gGrid->Mkdir(dirname)) < 0) {
-      cout << "Error in Mkdir " << dirname << endl;
-   }
-
-   TString fname("/alice_mdc/user/a/alimdc/rootdir/file");
-
-   if ((gGrid->AddFile(fname, "castor:///castor/cern.ch/test.root",
-                       100, "Alice::CERN::Castor",
-                       "003cce72-d0b2-1f30-aeff-c20c802abeef")) < 0) {
-      cout << "Error in AddFile " << fname << endl;
-   }
-
-4) Tagging Files in the catalogue
-
-   // adding a single attribute
-   if ((gGrid->AddAttribute(fname, "mdc4", "filesize", "1000")) < 0) {
-      cout << "Error adding attribute to " << fname << endl;
-   }
-
-   // adding multiple attributes
-   if ((gGrid->AddAttribute(fname, "mdc4", "filesize", "1000", "offset",
-                            "100")) < 0) {
-      cout << "Error adding attribute to " << fname << endl;
-   } // one can just continue the list of tags with more values ->
-     // variable argument list
+=========================================================================
+How to use the TGrid/TAlien/TAlienFile class V1.1 - Andreas.Peters@cern.ch
+=========================================================================
+
+
+TGrid-Plugin: TAlien
+====================
+
+To connect to Alien you have to connect to a running API service of your
+virtual organization.
+
+Creating <gGrid> instance:
+a) // connecting to an API service 
+
+    TGrid::Connect("alien://pcapiserv01.cern.ch:9000","aliprod);
+    
+    // connecting to an API service which is defined already by the
+    environement variables:
+		 export alien_API_HOST=...
+		 export alien_API_PORT=...
+		 export alien_API_USER=...
+    TGrid::Connect("alien://");
+
+    // connect to an API service with an authentication token established
+    previously with gShellq.
+
+b)  TGrid::Connect("alien://",0,0,"t");
+
+    In case a) the authentication is private to the process, while case b)
+    shares the authentication(session) with the shell, which has established
+    the session previously. Notice that a) is not thread-safe, while b) is!
+
+If you have executed TGrid::Connect(), the gGrid global variable
+should be set != 0.
+
+Some examples:
+
+- change the working directory
+  
+    gGrid->Cd("/alice/");  // => returns 1 for success, 0 for error
+  
+- get the working directory
+  
+    printf("GRID Working is %d",gGrid->Pwd());
+
+- list a directory
+
+    TGridResult* result = gGrid->Ls("/alice");                         
+    Int_t i=0;                                                         
+    while (result->GetFileName(i))                                    
+      printf("File %s\n",result->GetFileName(i++));
+    TGridResult* result = gGrid->Ls("/alice");                         
+    Int_t i=0;                                                           
+    while (result->GetFileName(i))                                    
+      printf("File %s\n",result->GetFileName(i++));
+
+- get all file permissions - using the GetKey function
+
+    TGridResult* result = gGrid->Ls("/alice","-la");                   
+    while (result->GetFileName(i))\                                    
+    printf("The permissions are %s\n",result->GetKey(i++,"permissions")  
+                                                                       
+    // => the defined keys for GetKey can be seen using result->Print();   
+
+
+- query files under a certain namespace tree
+
+    TGridResult* result = gGrid->Query("/alice/,"*.root");
+
+
+You can execute any existing command via the Command interface:
+    
+    TGridResult* result = gGrid->Command("ls -la /",0,2); 
+
+    // '0' switches of the output of stdout and stderr to the terminal
+    // '2' selects the result stream to be returned as TGridResult* :
+	  '0' returns stdout, 
+	  '1' returns stderr,
+	  '2' returns the result structure
+
+-> This command is equivalent to:
+   
+    gGrid->Ls("/","-la");
+
+You can print the stdout of the last command via:
+    gGrid->Stdout();
+
+You can print the stderr of the last command via:
+    gGrid->Stderr();
+        
+To see the result structure of a command, you can just use the 'Print' function for the
+TGridResult:
+
+	result->Print();
+
+
+
+TFile-Plugin: TAlienFile
+========================
+
+Files stored in Alien can be opened with the catalogue LFN or a GUID.
+To open a file by LFN use:
+
+	TFile* myfile = TFile::Open("alien:///alice/cern.ch/file.root");
+
+or
+	
+	TFile* myfile = TFile::Open("/alien/alice/cern.ch/file.root");
+	
+
+To open a file by GUID use:
+
+	TFile* myfile = TFile::Open("alien://<guid>");
+
+To address a certain storage element add to the URL
+	   "?se=ALICE::CERN::Castor";
+
+f.e.    TFile::Open("/alien/alice/cern.ch/file.root?se=ALICE::CERN::Castor");
+
+
+To open a ZIP file in an archive, use:
+
+	TFile::Open("/alien7alice/cern.ch/archivefile.zip#file.root");
+
+- this assumes, that archivefile.zip is an UNCOMPRESSED zip archive containing
+  'file.root'.
+- remember, that archives need to have the suffix '.zip' to be understood as
+  such.
+
+