diff --git a/python_appimage/appimage/relocate.py b/python_appimage/appimage/relocate.py
index 6923d31..b3bce88 100644
--- a/python_appimage/appimage/relocate.py
+++ b/python_appimage/appimage/relocate.py
@@ -44,12 +44,12 @@ def patch_binary(path, libdir, recursive=True):
         excluded = _excluded_libs
 
     ensure_patchelf()
-    rpath = '\'' + system(PATCHELF, '--print-rpath', path) + '\''
+    rpath = '\'' + system((PATCHELF, '--print-rpath', path)) + '\''
     relpath = os.path.relpath(libdir, os.path.dirname(path))
     relpath = '' if relpath == '.' else '/' + relpath
     expected = '\'$ORIGIN' + relpath + '\''
     if rpath != expected:
-        system(PATCHELF, '--set-rpath', expected, path)
+        system((PATCHELF, '--set-rpath', expected, path))
 
     deps = ldd(path)
     for dep in deps:
@@ -78,8 +78,8 @@ def relocate_python(python=None, appdir=None):
 
     # Set some key variables & paths
     if python:
-        FULLVERSION = system(python, '-c',
-            '"import sys; print(\'{:}.{:}.{:}\'.format(*sys.version_info[:3]))"')
+        FULLVERSION = system((python, '-c',
+            '"import sys; print(\'{:}.{:}.{:}\'.format(*sys.version_info[:3]))"'))
         FULLVERSION = FULLVERSION.strip()
     else:
         FULLVERSION = '{:}.{:}.{:}'.format(*sys.version_info[:3])
@@ -92,8 +92,8 @@ def relocate_python(python=None, appdir=None):
     APPDIR_SHARE = APPDIR + '/usr/share'
 
     if python:
-        HOST_PREFIX = system(
-            python, '-c', '"import sys; print(sys.prefix)"').strip()
+        HOST_PREFIX = system((
+            python, '-c', '"import sys; print(sys.prefix)"')).strip()
     else:
         HOST_PREFIX = sys.prefix
     HOST_BIN = HOST_PREFIX + '/bin'
diff --git a/python_appimage/commands/build/app.py b/python_appimage/commands/build/app.py
index 7ad096b..fad7cda 100644
--- a/python_appimage/commands/build/app.py
+++ b/python_appimage/commands/build/app.py
@@ -132,8 +132,8 @@ def execute(appdir, name=None, python_version=None, linux_tag=None,
         log('EXTRACT', '%s', os.path.basename(base_image))
         urlretrieve(base_image, 'base.AppImage')
         os.chmod('base.AppImage', stat.S_IRWXU)
-        system('./base.AppImage --appimage-extract')
-        system('mv squashfs-root AppDir')
+        system(('./base.AppImage', '--appimage-extract'))
+        system(('mv', 'squashfs-root', 'AppDir'))
 
 
         # Bundle the desktop file
@@ -212,12 +212,14 @@ def execute(appdir, name=None, python_version=None, linux_tag=None,
 
         # Bundle the requirements
         if requirements_list:
-            system('./AppDir/AppRun -m pip install -U '
-                   '--no-warn-script-location pip')
+            deprecation = 'DEPRECATION: Python 2.7 reached the end of its life'
+            system(('./AppDir/AppRun', '-m', 'pip', 'install', '-U',
+                   '--no-warn-script-location', 'pip'), exclude=deprecation)
             for requirement in requirements_list:
                 log('BUNDLE', requirement)
-                system('./AppDir/AppRun -m pip install -U '
-                       '--no-warn-script-location ' + requirement)
+                system(('./AppDir/AppRun', '-m', 'pip', 'install', '-U',
+                       '--no-warn-script-location', requirement),
+                       exclude=deprecation)
 
 
         # Bundle the entry point
diff --git a/python_appimage/utils/deps.py b/python_appimage/utils/deps.py
index 045361b..a30c0aa 100644
--- a/python_appimage/utils/deps.py
+++ b/python_appimage/utils/deps.py
@@ -47,7 +47,7 @@ def ensure_appimagetool():
         with TemporaryDirectory() as tmpdir:
             urlretrieve(os.path.join(baseurl, appimage), appimage)
             os.chmod(appimage, stat.S_IRWXU)
-            system('./' + appimage, '--appimage-extract')
+            system(('./' + appimage, '--appimage-extract'))
             copy_tree('squashfs-root', appdir)
 
     if not os.path.exists(APPIMAGETOOL):
@@ -87,7 +87,7 @@ def ensure_patchelf():
     with TemporaryDirectory() as tmpdir:
         urlretrieve(os.path.join(baseurl, 'rolling', appimage), appimage)
         os.chmod(appimage, stat.S_IRWXU)
-        system('./' + appimage, '--appimage-extract')
+        system(('./' + appimage, '--appimage-extract'))
         copy_file('squashfs-root/usr/bin/patchelf', patchelf)
     os.chmod(patchelf, stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO)
 
diff --git a/python_appimage/utils/docker.py b/python_appimage/utils/docker.py
index 1a79032..c9a0fe7 100644
--- a/python_appimage/utils/docker.py
+++ b/python_appimage/utils/docker.py
@@ -23,7 +23,7 @@ def docker_run(image, extra_cmds):
         raise ValueError('Unsupported Docker image: ' + image)
 
     log('PULL', image)
-    system('docker', 'pull', image)
+    system(('docker', 'pull', image))
 
     script = [
         'set -e',
diff --git a/python_appimage/utils/system.py b/python_appimage/utils/system.py
index ee471e9..1c82ea0 100644
--- a/python_appimage/utils/system.py
+++ b/python_appimage/utils/system.py
@@ -9,20 +9,35 @@ from .log import debug
 __all__ = ['ldd', 'system']
 
 
+try:
+    basestring
+except NameError:
+    basestring = (str, bytes)
 
-def system(*args):
+
+def system(args, exclude=None):
     '''System call with capturing output
     '''
     cmd = ' '.join(args)
     debug('SYSTEM', cmd)
 
+    if exclude is None:
+        exclude = []
+    elif isinstance(exclude, basestring):
+        exclude = [exclude]
+    else:
+        exclude = list(exclude)
+    exclude.append('fuse: warning:')
+
     p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE)
     out, err = p.communicate()
     if err:
         err = decode(err)
-        stripped = [line for line in err.split(os.linesep)
-                    if line and not line.startswith('fuse: warning:')]
+        stripped = [line for line in err.split(os.linesep) if line]
+        for pattern in exclude:
+            stripped = [line for line in stripped
+                        if not line.startswith(pattern)]
         if stripped:
             raise RuntimeError(err)
 
@@ -35,5 +50,5 @@ _ldd_pattern = re.compile('=> (.+) [(]0x')
 def ldd(path):
     '''Get dependencies list of dynamic libraries
     '''
-    out = system('ldd', path)
+    out = system(('ldd', path))
     return _ldd_pattern.findall(out)