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The Local Object

So far we've only seen running local commands, but there's more to the local object than this; it aims to represent the local machine, and it provides several useful APIs.

First, you should get acquainted with python, which is a command object that points to the current interpreter (i.e., sys.executable):

>>> local.python
<LocalCommand c:\python27\python.exe>
>>> local.python("-c", "import sys;print sys.version")
'2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)]\r\n'

Another useful member is which, which performs program name resolution in the executable PATH (returns the first match, or raises an exception if no match is found):

>>> local.which("ls")
<LocalPath C:\Program Files\Git\bin\ls.exe>
>>> local.which("nonexistent")
Traceback (most recent call last):
   [...]
plumbum.commands.CommandNotFound: ('nonexistent', [...])

Yet another is tempdir

Working Directory

The local.cwd attribute represents the current working directory. You can change it like so:

>>> local.cwd
<Workdir d:\workspace\plumbum>
>>> local.cwd.chdir("d:\\workspace\\plumbum\\docs")
>>> local.cwd
<Workdir d:\workspace\plumbum\docs>

But a much more useful pattern is to use it as a context manager, so it behaves like pushd/popd:

>>> with local.cwd("c:\\windows"):
...     print "%s:%s" % (local.cwd, (ls | wc["-l"])())
...     with local.cwd("c:\\windows\\system32"):
...         print "%s:%s" % (local.cwd, (ls | wc["-l"])())
...
c:\windows: 105
c:\windows\system32: 3013
>>> print "%s:%s" % (local.cwd, (ls | wc["-l"])())
d:\workspace\plumbum: 9

Environment

Similarly to cwd, local.env represents the local environment. It is a dictionary-like object that holds the environment variables, which you can get/set intuitively:

>>> local.env["JAVA_HOME"]
'C:\\Program Files\\Java\\jdk1.6.0_20'
>>> local.env["JAVA_HOME"] = "foo"

And like cwd again, you can work with env as a context manager; each level would have it's own private copy of the environment:

>>> with local.env(FOO="BAR"):
...     local.python("-c", "import os;print os.environ['FOO']")
...     with local.env(FOO="SPAM"):
...         local.python("-c", "import os;print os.environ['FOO']")
...     local.python("-c", "import os;print os.environ['FOO']")
...
'BAR\r\n'
'SPAM\r\n'
'BAR\r\n'
>>> local.python("-c", "import os;print os.environ['FOO']")
Traceback (most recent call last):
   [...]
ProcessExecutionError: Command line: ['c:\\python27\\python.exe', '-c', "import os;print os.environ['FOO']"]
Exit code: 1
Stderr:  | Traceback (most recent call last):
         |   File "<string>", line 1, in <module>
         |   File "c:\python27\lib\os.py", line 423, in __getitem__
         |     return self.data[key.upper()]
         | KeyError: 'FOO'

In order to make cross-platform-ness easier, the local.env object provides some convenience properties for getting the username (.user), the home path (.home), and the executable path (path) as a list. For instance:

>>> local.env.user
'sebulba'
>>> local.env.home
<Path c:\Users\sebulba>
>>> local.env.path
[<Path c:\python27\lib\site-packages\gtk-2.0\runtime\bin>, <Path c:\Users\sebulba\bin>, ...]
>>>
>>> local.which("python")
<Path c:\python27\python.exe>
>>> local.env.path.insert(0, "c:\\python32")
>>> local.which("python")
<Path c:\python32\python.exe>