fix arguments for commands in _process_posix

quotations marks could trivially break the command parsing. This has been
fixed by using the `args` kwarg, rather than trying to stuff it all into
one string.

previously-failing tests added

Closes gh-989.

IPython/utils/_process_posix.py

@@ -89,9 +89,8 b' class ProcessHandler(object):'
         file descriptors (so the order of the information in this string is the
         correct order as would be seen if running the command in a terminal).
         """
-        pcmd = self._make_cmd(cmd)
         try:
-            return pexpect.run(pcmd).replace('\r\n', '\n')
+            return pexpect.run(self.sh, args=['-c', cmd]).replace('\r\n', '\n')
         except KeyboardInterrupt:
             print('^C', file=sys.stderr, end='')
 
@@ -111,9 +110,8 b' class ProcessHandler(object):'
         file descriptors (so the order of the information in this string is the
         correct order as would be seen if running the command in a terminal).
         """
-        pcmd = self._make_cmd(cmd)
         try:
-            return pexpect.run(pcmd).replace('\r\n', '\n')
+            return pexpect.run(self.sh, args=['-c', cmd]).replace('\r\n', '\n')
         except KeyboardInterrupt:
             print('^C', file=sys.stderr, end='')
 
@@ -132,12 +130,13 b' class ProcessHandler(object):'
         # Get likely encoding for the output.
         enc = text.getdefaultencoding()
         
-        pcmd = self._make_cmd(cmd)
         # Patterns to match on the output, for pexpect.  We read input and
         # allow either a short timeout or EOF
         patterns = [pexpect.TIMEOUT, pexpect.EOF]
         # the index of the EOF pattern in the list.
-        EOF_index = 1  # Fix this index if you change the list!!
+        # even though we know it's 1, this call means we don't have to worry if
+        # we change the above list, and forget to change this value:
+        EOF_index = patterns.index(pexpect.EOF)
         # The size of the output stored so far in the process output buffer.
         # Since pexpect only appends to this buffer, each time we print we
         # record how far we've printed, so that next time we only print *new*
@@ -148,8 +147,7 b' class ProcessHandler(object):'
             # can set pexpect's search window to be tiny and it won't matter.
             # We only search for the 'patterns' timeout or EOF, which aren't in
             # the text itself.
-            #child = pexpect.spawn(pcmd, searchwindowsize=1)
-            child = pexpect.spawn(pcmd)
+            child = pexpect.spawn(self.sh, args=['-c', cmd])
             flush = sys.stdout.flush
             while True:
                 # res is the index of the pattern that caused the match, so we
@@ -179,11 +177,10 b' class ProcessHandler(object):'
             finally:
                 # Ensure the subprocess really is terminated
                 child.terminate(force=True)
+        # add isalive check, to ensure exitstatus is set:
+        child.isalive()
         return child.exitstatus
 
-    def _make_cmd(self, cmd):
-        return '%s -c "%s"' % (self.sh, cmd)
-
 
 # Make system() with a functional interface for outside use.  Note that we use
 # getoutput() from the _common utils, which is built on top of popen(). Using

IPython/utils/tests/test_process.py

@@ -86,12 +86,25 b' class SubProcessTestCase(TestCase, tt.TempFileMixin):'
         self.mktmp('\n'.join(lines))
 
     def test_system(self):
-        system('python "%s"' % self.fname)
+        status = system('python "%s"' % self.fname)
+        self.assertEquals(status, 0)
+
+    def test_system_quotes(self):
+        status = system('python -c "import sys"')
+        self.assertEquals(status, 0)
 
     def test_getoutput(self):
         out = getoutput('python "%s"' % self.fname)
         self.assertEquals(out, 'on stdout')
 
+    def test_getoutput_quoted(self):
+        out = getoutput('python -c "print 1"')
+        self.assertEquals(out.strip(), '1')
+        out = getoutput("python -c 'print 1'")
+        self.assertEquals(out.strip(), '1')
+        out = getoutput("python -c 'print \"1\"'")
+        self.assertEquals(out.strip(), '1')
+
     def test_getoutput(self):
         out, err = getoutputerror('python "%s"' % self.fname)
         self.assertEquals(out, 'on stdout')