Python one-liners
The Python interpreter command line arguments
Three useful command line arguments for Python one-liners:
graeme@psylocke:~/Projects/Presentations/MPUG_Jun2013$ python -h
usage: python [option] ... [-c cmd | -m mod | file | -] [arg] ...
Options and arguments (and corresponding environment variables):
-c cmd : program passed in as string (terminates option list)
-m mod : run library module as a script (terminates option list)
- : program read from stdin (default; interactive mode if a tty)
Useful programs & tools
Calendar:
python -m calendar
python -m calendar 1999
(type python -m calendar -h for more options)
ZIP and GZIP tools (for when you are stuck at a DOS prompt on a Windows box…)
python -m zipfile -l pcblib.zip
python -m zipfile -e pcblib.zip
python -m zipfile -c release.zip *.py
python -m gzip -d mydata.tar.gz
Pretty JSON printer:
python -m json.tool < mydata.json
Unicode character printers, by name or symbol:
python -c "import unicodedata; print unicodedata.name(unichr(0x2249))"
python -c "print unichr(0x2249)"
A simple webserver:
python -m SimpleHTTPServer
You can specify the port number if needed and there is also a CGI version:
python -m CGIHTTPServer
A basic SMTP server:
python -m smtpd -n -c DebuggingServer localhost:8025
Again, when you are stuck on a Windows box:
python -m telnetlib
There are similar command line tools for FTP, POP, SMTP (client as well as server)
and web.
pydoc tool to read & search Python documentation:
python -m pydoc
python -m pydoc -k
Python debugger:
python -m pdb
Interactive profile statistics browser:
python -m pstats
String processing:
python -c "import sys; print ''.join(x.capitalize() for x in sys.stdin)" < names.txt
Numerical processing:
python -c "import sys, math; print math.fsum(float(x) for x in sys.stdin)" < numbers.dat
(From Andrew Walker) "what is the easiest way to get a URL encoded password?" With a Python one liner!
python -c 'from getpass import getpass; from urllib import quote; print quote(getpass("Proxy Password: "))'
Clever/quirky one-liners
The Zen of Python:
python -m this
python -c "import this"
xkcd 353:
python -c "import antigravity"
Braces instead of whitespace?
python -c "from __future__ import braces"
A CS lecture:
python -c "import heapq; print heapq.__about__"
How does '-m' work?
if __name__ == '__main__':
print "do stuff..."
Some others that don't quite fit into this category
A bash function to grep on all Python files in the current directory:
pygrep () { grep $* *.py; }
Find the source code directory for a Python module (from here )
cdp () {
cd "$(python -c "import os.path as _, ${1}; \
print _.dirname(_.realpath(${1}.__file__[:-1]))"
)"
}
Other useful resources
-
The 'e' module
-
A great discussion at StackOverflow with lots more examples
-
pyp - "Pyp is a linux command line text manipulation tool similar to awk or sed, but which uses standard python string and
list methods as well as custom functions evolved to generate fast results in an intense production environment."
