Permission denied when using cat - even as root?
Question: How is it possible I am getting a permission denied using the below? I am
using python 2.7 and ubuntu 12.04

Below is my mapper.py file

    
    
    import sys
    import json
    
    for line in sys.stdin:
        line = json.loads(line)
        key = "%s:%s" % (line['user_key'],line['item_key'])
        value = 1
        sys.stdout.write('%s\t%s\n' % (key,value))
    

Below is my data file

    
    
    {"action": "show", "user_key": "heythat:htuser:32", "utc": 1368339334.568242, "id": "d518b7c5-a180-439b-8036-2bb40ca080cd", "item_key": "heythat:htitem:1000"}
    {"action": "click", "user_key": "heythat:htuser:32", "utc": 1368339334.573988, "id": "cc8c35ec-9e67-4ef8-a189-6116c7d0336a", "item_key": "heythat:htitem:1001"}
    {"action": "click", "user_key": "heythat:htuser:32", "utc": 1368339334.575226, "id": "6c457f9a-afc2-4b61-be2f-d4ea2863aa69", "item_key": "heythat:htitem:1002"}
    {"action": "show", "user_key": "heythat:htuser:32", "utc": 1368339334.575315, "id": "e0b08c30-459b-4f77-b9a4-05939457ab99", "item_key": "heythat:htitem:1000"}
    {"action": "click", "user_key": "heythat:htuser:32", "utc": 1368339334.57538, "id": "90084ea2-75c6-4b8a-bc22-9d9f2da1c0de", "item_key": "heythat:htitem:1002"}
    {"action": "show", "user_key": "heythat:htuser:32", "utc": 1368339334.57538, "id": "2f76a861-2b66-430a-b70d-2af6e1b9f365", "item_key": "heythat:htitem:1001"}
    {"action": "show", "user_key": "heythat:htuser:32", "utc": 1368339334.57538, "id": "282eec8a-7f6d-4ad3-917a-aae049062d87", "item_key": "heythat:htitem:1002"}
    {"action": "show", "user_key": "heythat:htuser:32", "utc": 1368339334.575447, "id": "bc48a6bc-f8f8-420e-9b80-0bd0c2bbde0d", "item_key": "heythat:htitem:1000"}
    {"action": "show", "user_key": "that:htuser:32", "utc": 1368339334.575513, "id": "14b49763-e2fe-4beb-bff6-f4b34b3d2ef3", "item_key": "that:htitem:1001"}
    {"action": "show", "user_key": "that:htuser:32", "utc": 1368339334.575596, "id": "983cbcf3-4375-4b3b-86ed-a8fbc86ff4b3", "item_key": "that:htitem:1002"}
    

Below is my error

    
    
     cat /home/ubuntu/workspace/logging/data.txt | /home/ubuntu/workspace/logging/mapper.py
    bash: /home/ubuntu/workspace/logging/mapper.py: Permission denied
    


Answer: Your `mapper.py` file needs to be executable (on some executable partition) so
`chmod a+x mapper.py`

The underlying [execve(2)](http://man7.org/linux/man-pages/man2/execve.2.html)
syscall is failing with

    
    
       EACCES Execute permission is denied for the file or a script or ELF
              interpreter.
    
       EACCES The file system is mounted noexec.
    

