Change Default Linux Shell

Needs sudo privileges: to change the default shell:

chsh

http://forums.devshed.com/unix-help-35/how-to-change-default-shell-52749.html

Host a Test email server for Django header debugging

Set the following in settings.py
EMAIL_HOST="localhost"
EMAIL_PORT="1025"

Run the following to host the test webserver

python -m smtpd -n -c DebuggingServer localhost:1025

http://docs.djangoproject.com/en/dev/topics/email/ 

Django Management Commands

Django syncdb without prompts
python manage.py syncdb --noinput

http://docs.djangoproject.com/en/dev/ref/django-admin/

Bash customize autocomplete

http://www.linuxjournal.com/content/more-using-bash-complete-command

Dynamic Fieldsets in Django Admin

Problem: the fieldsets option for the admin interface (classes defined in admin.py) requires that you explicitly list every single field in the model in the fieldset list that you pass to it.  This gets tedious if you add a field to a model, as you also have to add it to this admin.py.  Not very DRY.

Solution:
In models.py
from django.db import models
class My(models.Model):
    a = models.CharField(max_length=10)
    b = models.CharField(max_length=10)
    c = models.CharField(max_length=10)
    d = models.CharField(max_length=10)
    e = models.CharField(max_length=10)
    f = models.CharField(max_length=10)
    g = models.CharField(max_length=10)
    h = models.CharField(max_length=10)

In admin.py
from django.contrib import admin
from django.forms.models import fields_for_model
from f import models
class MyAdmin(admin.ModelAdmin):
    def __init__(self, *args, **kwargs):
        super(MyAdmin, self).__init__(*args, **kwargs)
        all_fields = set(fields_for_model(models.My))
        fieldset1_fields = ('e', 'f',)
        fieldset2_fields = ('g', 'h',)
        fieldset_fields = set(fieldset1_fields) | set(fieldset2_fields)
        rest_fields = list(all_fields - fieldset_fields)
        self.fieldsets = (
            (None, {
                'fields': rest_fields
            }),
            ('Fieldset 1', {
                'classes': ('collapse',),
                'fields': fieldset1_fields
            }),
            ('Fieldset 2', {
                'classes': ('collapse',),
                'fields': fieldset2_fields
            }),
        )
    models = models.My
admin.site.register(models.My, MyAdmin)


Thanks for the help lorochka85

Drill through a Login with Python

import urllib2
import urllib
import BeautifulSoup

# build opener with HTTPCookieProcessor
o = urllib2.build_opener( urllib2.HTTPCookieProcessor() )
urllib2.install_opener( o )

# assuming the site expects 'user' and 'pass' as query params
p = urllib.urlencode( { 'username': 'myusername', 'password': 'mypassword' } )

# perform login with params
f = o.open( 'https://www.mysite.com/login', p )
data = f.read()
f.close()

# second request should automatically pass back any
# cookies received during login... thanks to the HTTPCookieProcessor
f = o.open( 'http://www.mysite.com/home/' )
data = f.read()
f.close()

soup = BeautifulSoup.BeautifulSoup(data)

http://www.nomadjourney.com/2009/03/automatic-site-login-using-python-urllib2/

Python String format

Python Format dates into strings
from datetime import date
d1 = date(2010,01,23)
d2 = date(2010,01,23)
"%s - %s" % (d1.strftime("%m / %d / %Y"), d1.strftime("%m / %d / %Y"))

Python Unicode Convert

Convert weird unicode string characters to string:
import unicodedata
unicodedata.normalize('NFKD',unicode_string).encode('ascii','ignore')

Django module for helping convert things to ascii strings:
from django.utils.encoding import smart_str
smart_str('weird string goes here')

Another hack for removing unicode errors:
unicode('my weird string', errors='ignore')


http://docs.python.org/howto/unicode.html#the-unicode-type

matplotlib basics

Simple Plot
import matplotlib.pyplot as plt
plt.plot([1,2,3,4])
# plot a set of points (1,1) and (3,2)
plt.plot([1,3],[1,2],'ro')
# Or plot as a bunch of connect line segments
plt.plot([2,4,6],[2,4,6])
# set a label for the x and y axis
plt.ylabel('some numbers')
plt.xlabel('joe rocks')
# set the axis [xmin, xmax, ymin, ymax ]
plt.axis([0,6,0,5])
# 'show' the graph
plt.show()


Plot a function
As far as I can tell matplotlib cannot plot a continuous function.  
Instead, create a range of distinct numbers:

import numpy as np
import matplotlib.pyplot as plt
# create a range of numbers from 0 to 5. increment by .1
x = np.arange(0.,5.,.1)
# apply a function to that 
y = np.sin(x)
# plot with extra display params
plt.plot(x,y,linewidth=2.0, label='joeplot', color='blue')
plt.title(r'$\alpha_i > \beta_i$', fontsize=20)
plt.axis([0,5,-1,1])
plt.grid(True)
plt.show()

Make a cool heatmap
import numpy as np
import matplotlib.pyplot as plt
#x = y = np.linspace(-5, 5, 12)
# create a grid of 12 X coordinates and 12 Y coordinates 
# these coordinates will be used to represent specific locations on 
# the grid.  the meshgrid() basically creates a nice uniform coordinate grid
X,Y = np.meshgrid([1,2,3,4],[1,2,3])
# X,Y = np.meshgrid(x, y)
# these ravel functions basically make the 2d arrays created above into lists
x = X.ravel()
y = Y.ravel()
plt.subplot(111)
plt.hexbin(x,y,C=[1,2,3,3,2,2,3,3,2,3,3,4], gridsize=30)
cb = plt.colorbar()
cb.set_label('Heat Value')
plt.axis([x.min(), x.max(), y.min(), y.max()])
plt.grid(True)


http://stackoverflow.com/questions/2369492/generate-a-heatmap-in-matplotlib-using-a-scatter-data-set

Case Study Notes: install pyqrcode in a virtualenv on OSX

Kind of a buggy install.

mkdir qrcode; cd qrcode
virtualenv --distribute --no-site-packages ve
source ./ve/bin/activate
echo "pil" > requirements.pip
echo "http://svn.apache.org/repos/asf/lucene/pylucene/trunk/jcc" >> requirements.pip

wget http://downloads.sourceforge.net/pyqrcode/pyqrcode-0.2.1.tar.gz?use_mirror=

cd pyqrcode-0.2.1

# EDIT pyqrcode-0.2.1/Makefile
# change the call to jcc from
GENERATE=python -m jcc --jar $(LIBFILE) \
# TO
GENERATE=python -m jcc.__main__ --jar $(LIBFILE) \

make
make egg

# it will create qrcode-0.2.1-py2.6-macosx-10.6-universal.egg
# Edit qrcode-0.2.1-py2.6-macosx-10.6-universal.egg/qrcode/__init__.py
# change the line
_qrcode._setExceptionTypes(JavaError, InvalidArgsError)
# TO
_qrcode._set_exception_types(JavaError, InvalidArgsError)

pip -E ./ve/ install qrcode-0.2.1-py2.6-macosx-10.6-universal.egg

# http://pyqrcode.sourceforge.net/
# http://www.mail-archive.com/pythonmac-sig@python.org/msg09864.html
# http://mail-archives.apache.org/mod_mbox/lucene-pylucene-dev/200904.mbox/%3C49EEECAC.7070606@cheimes.de%3E

Installing MySQL-python (MySQLdb) in a virtualenv on OSX 10.6

There were two problems with the MySQL-Python package that I had when installing on OS X 10.6
1) First, an error saying "EnvironmentError: mysql_config not found" when setup.py is run (through pip or easy_install)
2) Second, an error saying "ImportError: dynamic module does not define init function(init_mysql) when importing MySQLdb" when 'import MySQLdb" is issued

Causes:
1) This is caused by the build script not being able to find a MySQL program called mysql_config. This program is used to determine metadata about the mysql install. For example, the command "mysql_config --cflags" reports the flags used to build mysql.
2) This is caused by a mismatch between the architectures that MySQL was built with and the architecture that MySQL-python installer is trying to build and install MySQL-python as. To find what arch MySQL was built as, run "mysql_config --cflags" (this was i386 in my case). OSX tries to build MySQL-python as x86_64. Therefore, there is a arch mismatch.

Solution:
1) Locate the mysql_config binary location and add the path to the MySQL-python/site.cfg file as a config directive: "mysql_config = /opt/local/bin/mysql_config5"
2) Use the arch x86_64 (64 bit) version of MySQL compiled through MacPorts, not a i386 (32 bit) version downloaded off the internet and installed as a dmg.

Summary:
Assuming the MacPorts version of MySQL is installed, both issues can be solved by adding the mysql_config = /opt/local/bin/mysql_config5 config directive to the MySQL-python/site.cfg file.

# SCRIPTED SOLUTION: Create a script called setup.sh and add the following lines
virtualenv --distribute --no-site-packages ve
source ./ve/bin/activate
pip install -E ./ve -r requirements.1.pip # other deps
export ARCHFLAGS="-arch x86_64"
pip install -E ./ve MySQL-python
echo "mysql_config = /opt/local/bin/mysql_config5" >> ./ve/build/MySQL-python/site.cfg
pip install -E ./ve MySQL-python


Resources:
http://groups.google.com/group/python-virtualenv/msg/cf4f3117faea476b?pli=1
http://birdhouse.org/blog/2009/02/21/python-mysql-connections-on-mac-os/
http://stackoverflow.com/questions/2111283/how-to-build-64-bit-python-on-os-x-10-6-only-64-bit-no-universal-nonsense

Python Pip Usage

Basic PIP install
pip install somepackage

Basic PIP uninstall
pip uninstall somepackage

Requirements file
# cat requirements.txt
MyApp
Framework==0.0.1
Library>=0.2

Installing using a requirements file
pip install -r requirements.pip

PIP Freezing requirements
pip freeze # lists all packages and the specific version installed. Useful for migrating

PIP install into virtualenv env
pip install -E ./env
pip install -E ./env -r requirements.pip # using a requirements file

Basic script for creating a virtualenv and installing requirements
virtualenv --distribute --no-site-packages ve
source ./ve/bin/activate
pip install -E ./ve -r requirements.pip
pip install -E ./ve -r requirements-test.pip

http://heisel.org/blog/2009/11/21/django-hudson/
http://pip.openplans.org/#freezing-requirements

Case Study Notes: install djangobb in virtualenv

Ubuntu 10.04 python 2.6 django 1.1

sudo apt-get build-dep python-psycopg2
sudo aptitude install python-dev

cd Sites
virtualenv --no-site-packages env
. ./env/bin/activate
pip install pil
pip install markdown2 Markdown
pip install django-registration
pip install djapian
pil install xapian
pip install psycopg2
easy_install -i http://downloads.egenix.com/python/index/ucs4/ egenix-mx-base
pip install http://code.djangoproject.com/svn/django/tags/releases/1.1.2/
hg clone http://hg.djangobb.org/djangobb/ djangobb
cd env/lib/python2.6/site-packages/
cp /usr/lib/python2.6/dist-packages/_xapian.so .
cp /usr/lib/python2.6/dist-packages/xapian.py .

# configure settings.py to use postgresql_psycopg2
# comment out the openid stuff

## http://www.saltycrane.com/blog/2009/07/using-psycopg2-virtualenv-ubuntu-jaunty/

Postgresql Basic Commands

Login to postgresql:
psql -d mydb -U myuser -W
psql -h myhost -d mydb -U myuser -W
psql -U myuser -h myhost "dbname=mydb sslmode=require" # ssl connection

Default Admin Login:
sudo -u postgres psql -U postgres
sudo -u postgres psql

List databases on postgresql server:
psql -l [-U myuser] [-W]

Turn off line pager pagination in psql:
\pset pager

Determine system tables:
select * from pg_tables where tableowner = 'postgres';

List databases from within a pg shell:
\l

List databases from UNIX command prompt:
psql -U postgres -l

Describe a table:
\d tablename

Quit psql:
\q

Switch postgres database within admin login shell:
\connect databasename

Reset a user password as admin:
alter user usertochange with password 'new_passwd';

Show all tables:
\dt

List all Schemas:
\dn

List all users:
\du

Load data into posgresql:
psql -W -U username -H hostname < file.sql

Dump (Backup) Data into file:
pg_dump -W -U username -h hostname database_name > file.sql

Increment a sequence:
SELECT nextval('my_id_seq');

Create new user:
CREATE USER jjasinski WITH PASSWORD 'myPassword';
# or
sudo -u postgres createuser jjasinski -W

Change user password:
ALTER USER Postgres WITH PASSWORD 'mypass';

Grant user createdb privilege:
ALTER USER myuser WITH createdb;

Create a superuser user:
create user mysuper with password '1234' SUPERUSER
# or even better
create user mysuper with password '1234' SUPERUSER CREATEDB CREATEROLE INHERIT LOGIN REPLICATION;
# or
sudo -u postgres createuser jjasinski -W -s

Upgrade an existing user to superuser: 
alter user mysuper with superuser;
# or even better
alter user mysuper with SUPERUSER CREATEDB CREATEROLE INHERIT LOGIN REPLICATION

Show Database Version:
SELECT version();

Change Database Owner:
alter database database_name owner to new_owner;

Copy a database:
CREATE DATABASE newdb WITH TEMPLATE originaldb;
http://www.commandprompt.com/ppbook/x14316

View Database Connections:
SELECT * FROM pg_stat_activity;

View show data directory (works on 9.1+; not on 7.x):
show data_directory;

Show run-time parameters:

show all;
select * from pg_settings;

Show the block size setting:
# show block_size;
 block_size
------------
 8192
(1 row)

Show stored procedure source:
SELECT prosrc FROM pg_proc WHERE proname = 'procname'

Grant examples:
# readonly to all tables for myuser
grant select on all tables in schema public to myuser;
# all privileges on table1 and table2 to myuser
grant all privileges on table1, table2, table3 to myuser;

Restore Postgres .dump file:
pg_restore --verbose --clean --no-acl --no-owner -h localhost -U myuser -d mydb latest.dump
source

Find all active sessions and kill them (i.e. for when needing to drop or rename db)
Source: http://stackoverflow.com/questions/5408156/how-to-drop-a-postgresql-database-if-there-are-active-connections-to-it

# Postgres 9.2 and above
SELECT pg_terminate_backend(pg_stat_activity.pid) 

FROM pg_stat_activity 

WHERE pg_stat_activity.datname = 'TARGET_DB' 

 AND pid <> pg_backend_pid();

# Postgres 9.1 and below
SELECT pg_terminate_backend(pg_stat_activity.procpid) 

FROM pg_stat_activity 

WHERE pg_stat_activity.datname = 'TARGET_DB' 

AND procpid <> pg_backend_pid();


Re-read postgres config without dropping connections (i.e. if postgres.conf or pg_hba.conf changes)
Source: http://www.heatware.net/databases/postgresql-reload-config-without-restarting/

/usr/bin/pg_ctl reload
or
SELECT pg_reload_conf();

Per user query logging (logs to to postgres logs):
alter role myuser set log_statement = 'all';


Sources:
http://www.devdaily.com/blog/post/postgresql/log-in-postgresql-database
http://forums.devshed.com/postgresql-help-21/how-do-you-turn-off-more-scroll-lock-at-psql-174831.htm
http://www.cyberciti.biz/faq/howto-add-postgresql-user-account/
http://archives.postgresql.org/pgsql-general/1998-08/msg00050.php
http://stackoverflow.com/questions/876522/creating-a-copy-of-a-database-in-postgres
http://stackoverflow.com/questions/1137060/where-does-postgresql-store-the-database

Recycle bin script

crm()
{
# pass this function the name of the directory that
# you want to backup and remove 
if [ -d "$1" ]
then
  cd "${1}/../"
else
  echo "Directory does not exist"
  return 1
fi

PWD=`pwd`
BKPFILES=`find $PWD -type -f`
BKPDIR="$HOME/.Trash"
daten=`date +%Y.%m.%d-%H.%M.%S`

for i in $BKPFILES
do
  echo "$i"
  DIRNAME="$BKPDIR"`echo ${i%/*}`
  FILENAME=`echo ${i##*/}`
  mkdir -p "$DIRNAME"
  cp -pf "$i" "${DIRNAME}/${FILENAME}.${daten}"
  #NEWFILE=`echo "$i" | sed 's|[ \/]|_|g'`
  print "$i"  "$NEWFILE"   " $DIRNAME"
done
rm -rf "$1"
cd - 
}

OSX Color LS

Color LS for Mac OX
alias ls='ls -G'

sftp notes

sftp using alternate port:
sftp -oPort=2222 username@host.com

sftp using alternate private key file:

sftp -o IdentityFile=/custom/file/location.pem username@host.com

http://www.unix.com/shell-programming-scripting/43334-sftp-scripting-help-required.html

Basic Python Development Server setup with Ubuntu 10.04

Quick setup guide

# config vi command line
echo "set -o vi" >> ~/.bashrc
. ~/.bashrc

# install packages
aptitude install vim openssh-server apache2 python-virtualenv python-mysqldb mysql-server libapache2-mod-php5 libapache2-mod-wsgi eclipse subversion nmap ubuntu-restricted-extras g++ git-gui virtualbox-ose php5-cli mdadm fabric python-dev mercurial

# eclipse development plugins
install pydev for eclipse
install subclipse for eclipse

# firefox development plugins
install firebug for firefox @ http://getfirebug.com/
install web developer for firefox @ https://addons.mozilla.org/en-US/firefox/addon/60/

# add google repo
deb http://dl.google.com/linux/deb/ stable non-free
aptitude update

cd /opt/
wget http://www.djangoproject.com/download/1.1.2/tarball/
wget http://www.djangoproject.com/download/1.2.1/tarball/
tar -xvf Django-1.1.2.tar.gz
tar -xvf Django-1.2.1.tar.gz
cd /usr/lib/python2.6/dist-packages
ln -s /opt/Django-1.2.1/django/ django

# mysql workbench download (64 bit version)
aptitude install libzip1 python-pysqlite2 # deps needed
http://dev.mysql.com/get/Downloads/MySQLGUITools/mysql-workbench-oss-5.2.22-1ubu1004-amd64.deb/from/http://mirror.services.wisc.edu/mysql/
dpkg -i mysql-workbench-oss-5.2.22-1ubu1004-amd64.deb

# setup postgresql
aptitude install postgresql pgadmin3 python-psycopg2

sudo su -
passwd postgres
su postgres
psql template1

The last instruction should open the psql shell, where you can run the following:

ALTER USER postgres WITH ENCRYPTED PASSWORD 'mypassword';

# Setup NX server (Google NeatX server)
sudo apt-get install python-software-properties && sudo add-apt-repository ppa:freenx-team
sudo apt-get update
sudo apt-get install neatx-server

## NOTE: if neatx gives a weird error, delete the session dirs on the server:
## /var/lib/neatx/sessions/some_dir/

https://help.ubuntu.com/community/FreeNX
http://programmingzen.com/2007/12/26/installing-django-with-postgresql-on-ubuntu/

Simple Network Test Script

This is a simple script to log network outages on a local network

root@ubuntu:/mnt/root/usr/local/bin# more lifeline
#!/bin/bash

PING='/bin/ping'
EXTHOST1='www.google.com'
EXTHOST2='sun.iwu.edu'
INTHOST='192.168.1.1'
LOG='/var/log/network_outages'
WAITTIME=120

echo "NETWORK STATUS SCRIPT: Started " `date` >> $LOG
while [ 1=1 ]
do
   dater=`date +%Y.%m.%d-%H.%M.%S`
   $PING -q -c1 $EXTHOST1
   ret=$?
   echo "RET: $ret"
   if [ $ret -ne 0 ]
   then
     echo "EXTERNAL_PING(1): outage detected $dater" >> $LOG
   fi

   dater=`date +%Y.%m.%d-%H.%M.%S`
   $PING -q -c1 $EXTHOST2
   ret=$?
   echo "RET: $ret"
   if [ $ret -ne 0 ]
   then
     echo "EXTERNAL_PING(2): outage detected $dater" >> $LOG
   fi

   $PING -q -c1 $INTHOST
   ret=$?
   echo "RET: $ret"
   if [ $ret -ne 0 ]
   then
     echo "INTERNAL_PING: outage detected $dater" >> $LOG
   fi

   sleep $WAITTIME
done

Simple HEX Editor

View file in Hex Editor
od -cx filename