[IPython-user] Capturing output from shell cmds

[Fernando Perez]

Ero Carrera wrote:

 >> Hello,
 >>
 >> I've just started to look into IPython and seems to have an incredible
 >> potential.
 >> But one thing I find it lacks (if it does) is the ability to capture the
 >> output from the executed shell commands. I found and modified a script
 >> to do so, but I'm curious to know whether I'm duplicating an already
 >> existing feature.


Place the stuff at the bottom in a python file in your ~/.ipython directory,
and set your ipythonrc file to load it with execfile:

execfile YOURFILE.py

This will define @capture as a new magic function which will capture and
return the output from any shell command.

You can then set this to a variable assigning to _.

Example:

In [8]: capture ls
Out[8]:
'inner.py\ninner.pyc\nMakefile\nmat_ten_inner_bz.h\nmat_ten_inner_dim_expand.h\nmat_ten_inner_np.h\nREADME\ntiming.py\n_utils.cpp\n_utils.o\n_utils.so'

In [9]: out = _

In [10]: print out
inner.py
inner.pyc
Makefile
mat_ten_inner_bz.h
mat_ten_inner_dim_expand.h
mat_ten_inner_np.h
README
timing.py
_utils.cpp
_utils.o
_utils.so


Note that I'm just using commands.getoutput, a standard python module which
you can use yourself to directly capture the output:

In [11]: out = commands.getoutput('ls')

In [12]: print out
inner.py
inner.pyc
Makefile
mat_ten_inner_bz.h
mat_ten_inner_dim_expand.h
mat_ten_inner_np.h
README
timing.py
_utils.cpp
_utils.o
_utils.so

So the magic @capture doesn't really add much which isn't in python to begin
with

Best,

f.


######### YOURFILE.py ################################
import commands

# fisrt define a function with the proper form:
def magic_capture(self,parameter_s=''):
      """Capture the output of system commands and return as a string"""

      return commands.getoutput(parameter_s)

# Add the new magic function to the class dict:
from IPython.iplib import InteractiveShell
InteractiveShell.magic_capture = magic_capture

# And remove the global name to keep global namespace clean.  Don't worry, the
# copy bound to IPython stays, we're just removing the global name.
del magic_capture