diff --git a/patoolib/programs/__init__.py b/patoolib/programs/__init__.py
index d03824d..5f14cd0 100644
--- a/patoolib/programs/__init__.py
+++ b/patoolib/programs/__init__.py
@@ -23,8 +23,7 @@ def extract_singlefile_standard (archive, encoding, cmd, **kwargs):
     outfile = util.get_single_outfile(kwargs['outdir'], archive)
     cmdlist.extend(['-c', '-d', '--', util.shell_quote(archive), '>',
         util.shell_quote(outfile)])
-    # note that for shell calls the command must be a string
-    return (" ".join(cmdlist), {'shell': True})
+    return (cmdlist, {'shell': True})
 
 
 def test_singlefile_standard (archive, encoding, cmd, **kwargs):
@@ -44,5 +43,4 @@ def create_singlefile_standard (archive, encoding, cmd, *args, **kwargs):
     cmdlist.extend(['-c', '--'])
     cmdlist.extend([util.shell_quote(x) for x in args])
     cmdlist.extend(['>', util.shell_quote(archive)])
-    # note that for shell calls the command must be a string
-    return (" ".join(cmdlist), {'shell': True})
+    return (cmdlist, {'shell': True})
diff --git a/patoolib/programs/bzip2.py b/patoolib/programs/bzip2.py
index 1b61c87..bbeb1ec 100644
--- a/patoolib/programs/bzip2.py
+++ b/patoolib/programs/bzip2.py
@@ -29,5 +29,4 @@ def create_bzip2 (archive, encoding, cmd, *args, **kwargs):
     cmdlist.extend(['-c', '-z', '--'])
     cmdlist.extend([util.shell_quote(x) for x in args])
     cmdlist.extend(['>', util.shell_quote(archive)])
-    # note that for shell calls the command must be a string
-    return (" ".join(cmdlist), {'shell': True})
+    return (cmdlist, {'shell': True})
diff --git a/patoolib/programs/compress.py b/patoolib/programs/compress.py
index 8fa0515..5414eaa 100644
--- a/patoolib/programs/compress.py
+++ b/patoolib/programs/compress.py
@@ -25,5 +25,4 @@ def create_compress (archive, encoding, cmd, *args, **kwargs):
     cmdlist.append('-c')
     cmdlist.extend([util.shell_quote(x) for x in args])
     cmdlist.extend(['>', util.shell_quote(archive)])
-    # note that for shell calls the command must be a string
-    return (" ".join(cmdlist), {'shell': True})
+    return (cmdlist, {'shell': True})
diff --git a/patoolib/programs/cpio.py b/patoolib/programs/cpio.py
index 0eb036b..d8a22c3 100644
--- a/patoolib/programs/cpio.py
+++ b/patoolib/programs/cpio.py
@@ -25,7 +25,7 @@ def extract_cpio (archive, encoding, cmd, **kwargs):
     if kwargs['verbose']:
         cmdlist.append('-v')
     cmdlist.extend(['<', util.shell_quote(os.path.abspath(archive))])
-    return (" ".join(cmdlist), {'cwd': kwargs['outdir'], 'shell': True})
+    return (cmdlist, {'cwd': kwargs['outdir'], 'shell': True})
 
 
 def list_cpio (archive, encoding, cmd, **kwargs):
@@ -50,4 +50,4 @@ def create_cpio(archive, encoding, cmd, *args, **kwargs):
         cmdlist[0:0] = findcmd
         cmdlist.append('-0')
     cmdlist.extend([">", util.shell_quote(archive)])
-    return (" ".join(cmdlist), {'shell': True})
+    return (cmdlist, {'shell': True})
diff --git a/patoolib/programs/rpm2cpio.py b/patoolib/programs/rpm2cpio.py
index 2ff289f..a1eab31 100644
--- a/patoolib/programs/rpm2cpio.py
+++ b/patoolib/programs/rpm2cpio.py
@@ -30,4 +30,4 @@ def extract_rpm (archive, encoding, cmd, **kwargs):
         r'"*\.\.*"']
     if kwargs['verbose']:
         cmdlist.append('-v')
-    return (" ".join(cmdlist), {'cwd': kwargs['outdir'], 'shell': True})
+    return (cmdlist, {'cwd': kwargs['outdir'], 'shell': True})
diff --git a/patoolib/programs/uncompress.py b/patoolib/programs/uncompress.py
index e552f53..3670158 100644
--- a/patoolib/programs/uncompress.py
+++ b/patoolib/programs/uncompress.py
@@ -25,5 +25,4 @@ def extract_compress (archive, encoding, cmd, **kwargs):
     outfile = util.get_single_outfile(kwargs['outdir'], archive)
     cmdlist.extend(['-c', util.shell_quote(archive), '>',
                     util.shell_quote(outfile)])
-    # note that for shell calls the command must be a string
-    return (" ".join(cmdlist), {'shell': True})
+    return (cmdlist, {'shell': True})
diff --git a/patoolib/util.py b/patoolib/util.py
index ec113d1..5d152fb 100644
--- a/patoolib/util.py
+++ b/patoolib/util.py
@@ -95,6 +95,9 @@ def run (cmd, **kwargs):
     if kwargs:
         log_info("    with %s" % ", ".join("%s=%s" % (k, shell_quote(str(v)))\
                                            for k, v in kwargs.items()))
+        if kwargs.get("shell"):
+            # for shell calls the command must be a string
+            cmd = " ".join(cmd)
     return subprocess.call(cmd, **kwargs)