Demonstrated the iPython approach by entering the following into an ipython REPL:

Python 2.7.12 (default, Nov 19 2016, 06:48:10) Type "copyright", "credits" or "license" for more information. IPython 2.4.1 -- An enhanced Interactive Python. ? -> Introduction and overview of IPython's features. %quickref -> Quick reference. help -> Python's own help system. object? -> Details about 'object', use 'object??' for extra details. In [1]: 2 ** 60 Out[1]: 1152921504606846976 In [2]: cd /tmp/testing /tmp/testing In [3]: ls pi.py pi.rb README src/ tests/ In [4]: cat pi.py import math print(math.pi) print(math.cos(math.pi)) In [5]: chmod a+x pi.py File "<ipython-input-5-b9e30b9b8e31>", line 1 chmod a+x pi.py ^ SyntaxError: invalid syntax In [6]: run pi 3.14159265359 -1.0 In [7]: system ruby pi.rb Out[7]: ['-0.9999999999964793', '-3.141592653589793'] In [8]: cat README Ciao, all you cool cats. Oh, and hey to all my dawgs. In [9]: def cat(arg=None): ...: return 'Meow!' ...: In [10]: cat Out[10]: <function __main__.cat> In [11]: cat() Out[11]: 'Meow!' In [12]: cat README File "<ipython-input-12-01ccd53eccb4>", line 1 cat README ^ SyntaxError: invalid syntax

In answer to your question, I haven’t looked to see why we have an array when calling the system function.

If you want to see what shell-like functions iPython has, type % and hit the Tab key, which shows something like:

In [13]: % Display all 122 possibilities? (y or n) %%! %doctest_mode %pfile %%HTML %ed %pinfo %%SVG %edit %pinfo2 %%bash %env %popd %%capture %gui %pprint %%debug %hist %precision %%file %history %profile %%html %install_default_config %prun %%javascript %install_ext %psearch %%latex %install_profiles %psource %%perl %killbgscripts %pushd %%prun %ldir %pwd %%pypy %less %pycat %%python %lf %pylab %%python2 %lk %quickref %%python3 %ll %recall %%ruby %load %rehashx %%script %load_ext %reload_ext %%sh %loadpy %rep %%svg %logoff %rerun %%sx %logon %reset %%system %logstart %reset_selective %%time %logstate %rm %%timeit %logstop %rmdir %%writefile %ls %run %alias %lsmagic %save %alias_magic %lx %sc %autocall %macro %store %autoindent %magic %sx %automagic %man %system %bookmark %matplotlib %tb %cat %mkdir %time %cd %more %timeit %clear %mv %unalias %colors %notebook %unload_ext %config %page %who %cp %paste %who_ls %cpaste %pastebin %whos %debug %pdb %xdel %dhist %pdef %xmode %dirs %pdoc