Python subprocess library: Running grep command from Python

Abstraction: Using Python subprocess.Popen to chain catdoc and grep for doc file search

Key points:

• Uses subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE) then .communicate() to capture output
• catdoc extracts plain text from .doc files; grep then searches the extracted text for a keyword
• Common bug: placing shell redirect > as a list element in args — shell redirection must be handled differently or use shell=True with a string
• When using shell=True, command should be a single string, not a list; mixing the two causes silent failures

Connections: Python Scripting · Shell Integration

Source: http://stackoverflow.com/questions/12765207/python-subprocess-library-running-grep-command-from-python