simple fix to run - only parse result if one is returned

CHANGELOG.md

@@ -17,6 +17,7 @@ The client here will eventually be released as "spython" (and eventually to
 singularity on pypi), and the versions here will coincide with these releases.
 
 ## [master](https://github.com/singularityhub/singularity-cli/tree/master)
+ - flexible error printing given command to terminal fails (0.0.43)
  - adding name_by_commit and name_by_hash to pull (0.0.42)
  - adding nvidia flag as nv argument (with default False) to run/exec (0.0.41)
  - fixing bug in shell.py, cli should be client (0.0.40)

spython/main/base/command.py

@@ -116,7 +116,7 @@ def run_command(self, cmd, sudo=False, capture=True):
     result = run_cmd(cmd, sudo=sudo, capture=capture, quiet=self.quiet)
     message = result['message']
     return_code = result['return_code']
-        
+
     if result['return_code'] == 0:
         if len(message) == 1:
             message = message[0]

spython/main/run.py

@@ -91,10 +91,11 @@ def run(self,
     else:
         return stream_command(cmd, sudo=sudo)
 
-    result = result.strip('\n')
-
-    try:
-        result = json.loads(result)
-    except:
-        pass
-    return result
+    if result:
+        result = result.strip('\n')
+
+        try:
+            result = json.loads(result)
+        except:
+            pass
+        return result

spython/version.py

@@ -18,7 +18,7 @@
 
 
 
-__version__ = "0.0.42"
+__version__ = "0.0.43"
 AUTHOR = 'Vanessa Sochat'
 AUTHOR_EMAIL = 'vsochat@stanford.edu'
 NAME = 'spython'
@@ -28,4 +28,4 @@
 LICENSE = "LICENSE"
 
 INSTALL_REQUIRES = (
-)
+)