diff --git a/html/inc/sandbox.inc b/html/inc/sandbox.inc
index 620c8e4d5a0..6ec90b6d972 100644
--- a/html/inc/sandbox.inc
+++ b/html/inc/sandbox.inc
@@ -69,7 +69,7 @@ function sandbox_parse_info_file($user, $name) {
     if ($info) {
         return $info;
     }
-    [$size, $md5] = get_file_info("$dir/$name");
+    [$md5, $size] = get_file_info("$dir/$name");
     write_info_file($info_path, $md5, $size);
     return [$md5, $size];
 }
diff --git a/html/user/buda.php b/html/user/buda.php
index 480542b7253..c5271ae0586 100644
--- a/html/user/buda.php
+++ b/html/user/buda.php
@@ -114,7 +114,7 @@ function variant_view() {
     }
     end_table();
     show_button_small(
-        "buda.php?action=variant_delete&app=$dir&variant=$variant",
+        "buda.php?action=variant_delete&app=$app&variant=$variant",
         'Delete variant'
     );
     page_tail();
@@ -167,6 +167,7 @@ function copy_and_stage_file($user, $fname, $dir, $app, $variant) {
 function variant_action($user) {
     global $buda_root;
     $variant = get_str('variant');
+    if (!$variant) $variant = 'cpu';
     if (!is_valid_filename($variant)) die('bad arg');
     $app = get_str('app');
     if (!is_valid_filename($app)) die('bad arg');
@@ -300,7 +301,7 @@ function app_form() {
 function app_action() {
     global $buda_root;
     $name = get_str('name');
-    if (!is_valid_filename($name)) die('bad arg');
+    if (!is_valid_filename($name)) die("bad arg: $name");
     $dir = "$buda_root/$name";
     if (file_exists($dir)) {
         error_page("App $name already exists.");
diff --git a/html/user/buda_submit.php b/html/user/buda_submit.php
index 3a56969952b..36aab6b9c4b 100644
--- a/html/user/buda_submit.php
+++ b/html/user/buda_submit.php
@@ -81,8 +81,8 @@ function unzip_batch_file($user, $batch_file) {
 
 // Scan a batch dir.
 // Check its validity:
-// - Top level can have only infiles (shared)
-// - Subdirs (job dirs) can have only remaining infiles and possibly cmdline
+// - optional dir 'shared_input_files' has shared input files
+// - other dirs (job dirs) can have only remaining infiles and possibly cmdline
 //
 // Return a structure describing its contents, and the md5/size of files
 //
diff --git a/html/user/sandbox.php b/html/user/sandbox.php
index ad493866850..9fa6037b97e 100644
--- a/html/user/sandbox.php
+++ b/html/user/sandbox.php
@@ -41,7 +41,7 @@ function list_files($user, $notice) {
     }
     echo "
         <p>
-        <h3>Upload files</h3>
+        <h3>Upload files from this computer</h3>
         <p>
         NOTE: if you upload text files from Windows,
         they will be given CRLF line endings.
@@ -63,6 +63,15 @@ function list_files($user, $notice) {
     form_input_textarea('Contents', 'contents');
     form_submit('OK');
     form_end();
+    echo "
+        <hr>
+        <h3>Get web file</h3>
+    ";
+    form_start('sandbox.php', 'post');
+    form_input_hidden('action', 'get_file');
+    form_input_text('URL', 'url');
+    form_submit('OK');
+    form_end();
     echo "
         <hr>
         <h3>Sandbox contents</h3>
@@ -150,6 +159,19 @@ function add_file($user) {
     list_files($user, $notice);
 }
 
+function get_file($user) {
+    $dir = sandbox_dir($user);
+    $url = post_str('url');
+    $fname = basename($url);
+    $path = "$dir/$fname";
+    if (file_exists($path)) {
+        error_page("File $fname exists; delete it first.");
+    }
+    copy($url, $path);
+    $notice = "Fetched file from <strong>$url</strong><br/>";
+    list_files($user, $notice);
+}
+
 // delete a sandbox file.
 //
 function delete_file($user) {
@@ -189,6 +211,7 @@ function view_file($user) {
 case '': list_files($user,""); break;
 case 'upload_file': upload_file($user); break;
 case 'add_file': add_file($user); break;
+case 'get_file': get_file($user); break;
 case 'delete_file': delete_file($user); break;
 case 'download_file': download_file($user); break;
 case 'view_file': view_file($user); break;
diff --git a/samples/docker_wrapper/docker_wrapper.cpp b/samples/docker_wrapper/docker_wrapper.cpp
index 2d304d28c82..0d60234f055 100644
--- a/samples/docker_wrapper/docker_wrapper.cpp
+++ b/samples/docker_wrapper/docker_wrapper.cpp
@@ -321,21 +321,20 @@ int container_op(const char *op) {
 }
 
 // Clean up at end of job.
-// Show log output if verbose;
+// Show log output.
 // remove container and image
 //
 void cleanup() {
     char cmd[1024];
     vector<string> out;
 
-    if (verbose) {
-        sprintf(cmd, "logs %s", container_name);
-        docker_conn.command(cmd, out);
-        fprintf(stderr, "container log:\n");
-        for (string line : out) {
-            fprintf(stderr, "   %s\n", line.c_str());
-        }
+    sprintf(cmd, "logs %s", container_name);
+    docker_conn.command(cmd, out);
+    fprintf(stderr, "stderr from container:\n");
+    for (string line : out) {
+        fprintf(stderr, "%s\n", line.c_str());
     }
+    fprintf(stderr, "stderr end\n");
 
     container_op("stop");
 
diff --git a/samples/docker_wrapper/test_buda/Dockerfile_worker_1 b/samples/docker_wrapper/test_buda/Dockerfile_worker_1
deleted file mode 100644
index d897eaff2b1..00000000000
--- a/samples/docker_wrapper/test_buda/Dockerfile_worker_1
+++ /dev/null
@@ -1,3 +0,0 @@
-FROM debian
-WORKDIR /app
-CMD ./main_2.sh
diff --git a/samples/docker_wrapper/test_buda/Dockerfile_worker_2 b/samples/docker_wrapper/test_buda/Dockerfile_worker_2
new file mode 100644
index 00000000000..40503e3b86d
--- /dev/null
+++ b/samples/docker_wrapper/test_buda/Dockerfile_worker_2
@@ -0,0 +1,4 @@
+FROM debian
+WORKDIR /app
+ENV ARGS ""
+CMD ./main_3.sh ${ARGS}
diff --git a/samples/docker_wrapper/test_buda/main_2.sh b/samples/docker_wrapper/test_buda/main_2.sh
deleted file mode 100644
index f07fd7a2a69..00000000000
--- a/samples/docker_wrapper/test_buda/main_2.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-#! /bin/bash
-
-./worker_3_x86_64-pc-linux-gnu --nsecs 20 in out
diff --git a/samples/docker_wrapper/test_buda/main_3.sh b/samples/docker_wrapper/test_buda/main_3.sh
new file mode 100644
index 00000000000..b45f6a05459
--- /dev/null
+++ b/samples/docker_wrapper/test_buda/main_3.sh
@@ -0,0 +1,3 @@
+#! /bin/bash
+
+./worker_4_x86_64-pc-linux-gnu $ARGS in out
diff --git a/samples/worker/Makefile b/samples/worker/Makefile
index 0eb83b22a7c..67d7ef252e7 100644
--- a/samples/worker/Makefile
+++ b/samples/worker/Makefile
@@ -1,4 +1,4 @@
-CXXFLAGS += -g
+#CXXFLAGS += -g
 CXX ?= g++
 
 ifdef ANDROID
@@ -20,8 +20,8 @@ clean: distclean
 distclean:
 	rm -f $(PROGS) $(addsuffix .exe, $(PROGS)) *.o
 
-worker$(WORKER_RELEASE_SUFFIX): worker.o
-	$(CXX) $(CXXFLAGS) $(CPPFLAGS) $(LDFLAGS) -o worker$(WORKER_RELEASE_SUFFIX) worker.o
+worker$(WORKER_RELEASE_SUFFIX): worker.cpp
+	$(CXX) $(CXXFLAGS) $(CPPFLAGS) $(LDFLAGS) -o worker$(WORKER_RELEASE_SUFFIX) worker.cpp
 
 install: all
 
diff --git a/samples/worker/worker.cpp b/samples/worker/worker.cpp
index 77f591d56f8..9af923bb487 100644
--- a/samples/worker/worker.cpp
+++ b/samples/worker/worker.cpp
@@ -47,59 +47,72 @@ static double do_a_giga_flop(int foo) {
     return x;
 }
 
-void copy_uc(FILE* fin, FILE* fout) {
-    int c;
+int copy_uc(FILE* fin, FILE* fout) {
+    int c, n=0;
     while (1) {
         c = fgetc(fin);
         if (c == EOF) break;
         fputc(toupper(c), fout);
+        n++;
     }
+    return n;
 }
 
 int main(int argc, char** argv) {
+    const char *infile=NULL, *outfile=NULL;
     FILE* in=0, *out=0;
     int i, nsecs = 0;
 
     for (i=1; i<argc; i++) {
         if (!strcmp(argv[i], "--nsecs")) {
             nsecs = atoi(argv[++i]);
-        } else if (!in) {
-            if (!strcmp(argv[i], "stdin")) {
-                in = stdin;
-            } else {
-                in = fopen(argv[i], "r");
-                if (!in) {
-                    fprintf(stderr, "missing input file %s\n", argv[i]);
-                    exit(1);
-                }
-            }
+        } else if (!infile) {
+            infile = argv[i];
         } else {
-            if (!strcmp(argv[i], "stdout")) {
-                out = stdout;
-            } else {
-                out = fopen(argv[i], "w");
-                if (!out) {
-                    fprintf(stderr, "missing output file %s\n", argv[i]);
-                    exit(1);
-                }
-            }
+            outfile = argv[i];
         }
     }
-    if (!in || !out) {
-        fprintf(stderr, "worker: no files specified\n");
+    if (!infile) {
+        fprintf(stderr, "worker: no input file specified\n");
+        exit(1);
+    }
+    if (!outfile) {
+        fprintf(stderr, "worker: no output file specified\n");
         exit(1);
     }
+    fprintf(stderr, "worker: infile=%s outfile=%s nsecs=%d\n",
+        infile, outfile, nsecs
+    );
+
+    if (!strcmp(infile, "stdin")) {
+        in = stdin;
+    } else {
+        in = fopen(infile, "r");
+        if (!in) {
+            fprintf(stderr, "missing input file %s\n", infile);
+            exit(1);
+        }
+    }
+    if (!strcmp(outfile, "stdout")) {
+        out = stdout;
+    } else {
+        out = fopen(outfile, "w");
+        if (!out) {
+            fprintf(stderr, "can't open output file %s\n", outfile);
+            exit(1);
+        }
+    }
 
     fprintf(stderr, "worker: starting\n");
 
-    copy_uc(in, out);
+    int nchars = copy_uc(in, out);
 
     i=0;
     while (clock()/(double)CLOCKS_PER_SEC < nsecs) {
         do_a_giga_flop(i++);
     }
 
-    fprintf(stderr, "worker: done\n");
+    fprintf(stderr, "worker: done; copied %d chars\n", nchars);
     return 0;
 }
 
diff --git a/version.h b/version.h
index 776b84a2ed8..9ac89d03b6d 100644
--- a/version.h
+++ b/version.h
@@ -27,7 +27,7 @@
 #define VBOXWRAPPER_RELEASE 26209
 
 // worker version number
-#define WORKER_RELEASE 2
+#define WORKER_RELEASE 4
 
 // client version number as string
 #define BOINC_VERSION_STRING "8.1.0"