Replacing folders on a network with psexec and xcopy

rem We can run a process remotely with psexec
rem
rem cmd /C allows us to run a process in a cmd window and it automatically terminates

for /l %a in (1,1,50) do psexec \\station-%a cmd /C "move c:\path\to\folder c:\path\to\backup"

rem Now lets replace that folder with a new one using xcopy
rem
rem We use our local copy of the folder c:\path\to\folder and copy it to each station
rem
rem /S /E /H /I switches for xcopy ensure that we get hidden files, sub directories, and empty directories. /I assumes that the destination is a folder.

for /l %a in (1,1,50) do start cmd /k "xcopy /S /E /H /I c:\path\to\folder \\station-%a\c$\path\to\folder"

Get mac serial no from terminal

system_profiler SPHardwareDataType | grep "Serial Number" | sed 's/Serial Number://'

Php basics : error handling, tests, array functs, classes, and scope

Checking if a file exists

if (file_exists($some_file)){
...
}

Basic Error Handling

function($var) or exit("some error");


Printing an array

print_r();


Creating a class

class SomeClass{

private some_var;

public function SomeClass(){}

public function new_fun($r){
print_r($r);
echo $this->some_var;

}

}


Defining an array

$my_array = array('elem1','elem2');

Adding an array element

array_push($array,$elem)


Checking if a key exists

array_key_exists("some_name",$r)


Using a global var in a function

global $global_var;

JQuery basics : working with divs and text boxes, and checking for null elements

Adding text to a div's innerHTML

$("div#some_div").append(s);


Getting text from a div

var text = $("div#some_div" ).html();


Getting/Setting value from text box

var text = $("#some_textbox").val();
$("#some_textbox").val("bla");


Checking if document element is null

if (!$("#some_elem").length){
...

}

Get the distance between two latitude/longitude points in km (example)

Here is a python script to convert lat/lng point to meters. It expects the points to be entered in as decimal degrees. It outputs the distance in km.

For example:

python distlatlng.py 36.12 -86.67 33.94 -118.40
the distance in km is 2887.25995061

#uses the haversine formula
# based on code from http://www.movable-type.co.uk/scripts/latlong.html
import math, sys

def main(*args):
 if len(args) < 5:
  print args[0]," lng1 lat1 lng2 lat2 (finds distance between two lat/lng pairs)"
  return
 lat1 = float(args[1]) 
 lng1 = float(args[2])
 lat2 = float(args[3])
 lng2 = float(args[4])
 radius = 6372.8 # earth's mean radium in km
 dlat = math.radians(lat2-lat1)
 dlng = math.radians(lng2-lng1)
 a = math.sin(dlat/2) * math.sin(dlat/2) + math.cos(math.radians(lat1)) * math.cos(math.radians(lat2)) * math.sin(dlng/2)*math.sin(dlng/2)
 c = 2*math.atan2(math.sqrt(a),math.sqrt(1-a))
 dist = radius*c 
 print "the distance in km is " , dist
 
 
if __name__ == "__main__":
 main(*sys.argv)

Python basics : math functions, main funct

Math functions
#Unfortunately, you need to import math, but python has a nice library of math functions

import math
math.pow(2,3)
math.cos(math.pi/2)  #<-- radians!
math.pi
math.sqrt(4)

Main function

#Making a main function in Python is a little tricky. Here is an example:

def main(*args):
        if len(args) < 4:
                return
      
        print "main : args[0] ", args[0], " args[1]", args[1]
        print "(main) : args[1] ", args[2]
        print "(main) : args[3] ", args[3]
      
if __name__ == "__main__":

Mysql -- get table engine type

Get table engine type

You have to go to the mysql system database 1st

This allows you to see which type of table engine you're using

Common types:

myisam: doesn't support the features listed below for innodb
innodb (default) : supports r-trees (good for spatial extensions), enforces foreign keys, and supports transactions


select table_name, engine from tables where table_schema = "vsn";