terryoy

# install virtualenv to manage the environment
sudo apt-get install python-virtualenv

# create site folder
mkdir mysite
cd mysite

# activatet the virtualenv environment
virtualenv venv
source venv/bin/activate

terryoy

# convert text files to all lower case
$ tr '[:upper:]' '[:lower:]' < input.txt > output.txt
 
# Convert Data Stored in a Shell Variable From UPPPER to lowercase
$ echo $VAR_NAME | tr '[:upper:]' '[:lower:]'
# Convert Data Stored in a Shell Variable From lowercase to UPPER
$ echo $VAR_NAME | tr '[:lower:]' '[:upper:]'

# job control:
# ctrl+z - suspend a job and put into background

terryoy

# Checkout source
svn co SVN_URL [PATH] [--username USERNAME] [--password PASSWORD] [-r REVISION] 

# Add an unversioned(new) FILE or DIR to the version control system
svn add FILE

# show the current conflict/modified/new status of working directories and files 
svn status
# You should always do a manual svn status --show-updates before trying to commit 
# changes in order to check that everything is OK and ready to go.

terryoy

# install userena
pip install django-userena

# a simple catpcha for django
pip install  django-simple-captcha

# install dependencies for pil and captcha
sudo apt-get install libjpeg libjpeg-dev libfreetype6 libfreetype6-dev zlib1g-dev
# install pil
pip install pil

terryoy

# Reference: http://www.gentoo.org/doc/zh_cn/gentoo-x86-quickinstall.xml
##########################################################################
##### part 1: boot with gentoo minimal #####

# boot
gentoo

# config network
net-setup eth0
ifconfig

terryoy

### emerge package management (need root access) ###
### "emerge" is a tool manipulating Gentoo's package management tool "Portage" ###

# update portage tree
emerge --sync

# search package
emerge --search pdf
emerge --searchdesc pdf

terryoy

# create and format the partitions
fdisk /dev/sda
# n (new partition)
# +100M (for /boot)
# n 
# +15G (for / including /usr)
# n 
# +8G (for /var)
# n
# (for the rest, extended)

terryoy

$ vi hello.c
# #include <stdio.h>
# 
# int main() {
#   printf("Hello world!\n");
#   exit(0);
# }

$ gcc -o hello hello.c
hello.c: In function ‘main’:

terryoy

###  IO redirecting ###

# "2" is stderr
kill -HUP >killout 2>killerr.txt
# add stderr to the same file as stdout
kill -l 1234 >killout 2>&1
# output to "Recycle Bin"
kill -l 1234 >/dev/null 2>&1
# redirect stdin
more < killout.txt

terryoy

# Scan Serial Ports (for Serial Communication Device, such as GPS, Arduino, etc.)
import serial

def scanports():
  found = False
  for i in range(64):
    try:
      ser = serial.Serial(i) # for windows version
      # in linux, you should use "named port" to open(e.g. serial.Serial('/dev/ttyACM0'), etc.)
      ser.close()