Command execution¶

Use short method names:

   1 def S(arg):
   2   """returns string of executed command arg"""
   3   return os.popen(arg).read()
   4 
   5 def SN(arg):
   6   """returns list of executed command arg"""
   7   return os.popen(arg).read().split('\n')
   8 
   9 def SP(arg):
  10   """prints string of executed command arg"""
  11   print S(arg)
  12 
  13 def SNP(arg):
  14   """prints with lines list executed command arg"""
  15   for i in SN(arg):
  16     print i

Command execution is the one thing an InteractiveShell has to be good at. Typing S(“<command>”) is too much overhead for command execution. Still, a mixture of bash style command execution and shell programming with Python would be great.

I’d want the simple style of command execution from bash available:

cd /foo/bar

But also the Python style for more complex commands:

os.setcwd('/foo/bar')

Some ways to execute the bash-style command:

• Use os.popen(<command>).

• Map all commands to Python functions: cd(), less(), all taking a list of strings as arguments.

• Completely separate bash-style commands from Python commands, executing it with bash.

– JohannesGijsbers 2002-12-07 03:34:05

There is a project that attempts to acheive this. Quasi (http://quasi-shell.sourceforge.net/) provides a shell within which Python can be freely mixed with OS (and certain database) commands. – BenLast

• This sounds a lot like lwickjr/Modules/Alias.py when coupled with a module of shell-command functions. See lwickjr/Modules for further information.

  • –lwickjr

Path manipulation¶

The os.path module provides a good set of functions for path manipulation, but you might also want to split the path at the root:

   1 import re
   2 def splitroot(s):
   3   if "/" not in s:
   4     return '',s
   5   if s[0] == '/':
   6     s = s[1:]
   7   m = re.match("(.*?)/(.*)$",s)
   8   return m.groups()

awk comparables¶

Simply use the re module. It’s a fuller set of regular expressions. Create a wrapper function for a utility for this if you want call it inlinegrep.

Limitations¶

The killall function was rejected by the BDFL. As far as I can see from the previous version of this page, Guido rejected it because it isn’t in POSIX. I couldn’t find any references on this in the mailing list archives. Anyone?

See also:

• The Perl Shell