The Power of scripting

Marco Fioretti ([email protected]) September 2010, Prishtinahttp://mfioretti.com Software Freedom Conference Kosovahttp://stop.zona-m.net Some rights reserved

The Power of scriptingwhy and how to promote

scripting languages

in schools and small businesses

Marco Fiorettihttp://mfioretti.com

http://stop.zona-m.net

2Marco Fioretti ([email protected]) August 2010, Prishtinahttp://mfioretti.com Software Freedom Conference Kosovahttp://stop.zona-m.net Some Rights Reserved

Marco Fioretti

Member ofOpenDocument Fellowship (www.opendocumentfellowship.com)

Digistan.org (www.digistan.org)

Writer for Linux Journal, Linux Format, Pc Professionale and other magazines

Author of the Family Guide to Digital Freedom (http://digifreedom.net)

Co-author of the O'Reilly Open Government book

Home page and writings:

http://mfioretti.com

http://stop.zona-m.net

Author introduction

http://digifreedom.net/


What the command line and scripting

languages really are

Practical examples

Conclusions: why scripting languages are

good for schools and small businesses

Agenda


A GUI is an environment in which the computer

visually tells you what can be done, showing

possible choices in buttons or menus

And the user manually indicates (mouse clicks) what

he or she wants to do. Every time...

What is a graphical user interface (GUI)?


A command line is a place, inside a text terminal

window, where the user can write, that is declare in

writing, whatever he or she wants the computer to do

Depending on the context, a shell is either an

environment in which the user can give commands to

the computer, or an interpreter of those commands

What are shells,command lines, terminals?


The GUI shows what is the content of a folder:

GUI vs Command line: visual comparison


A shell tells the user what is the content of a folder



To move files and folders in GUIs, the user must point to

those objects and to the place where they should go


Select object Drag it to destination


To move files and folders in the terminal, the user tells the

computer where those objects should go


mv = “move this here”


There are many cases where a GUI is much more efficient (e.g.

picture editing, drawings...)

But also many others where the difference between GUI and

command line users is the same that there is between a toddler

pointing at objects and an adult saying “I need to do this”

Ignorance of real speech (GUI) = much more communication

limits, that is much more effort and time wasted to tell the

computer what it must do

GUI vs Command line: what's the difference?


The fact that textual commands don't need to be given in real time!

To repeat gestures you must either repeat them or make a movie

To repeat many text commands, you can just type them all, once,

into a file...

...that the computer is able to read by itself!

And all this is much, much, much simpler than real

programming!

And another HUGE difference is...


A scripting language is a computer language which has an

interpreter, that is a separate program that:

Reads the commands written into files called scripts, one at a

time

And executes those commands, one at a time

Without asking the user to take care of variable declarations or

typing, memory allocation, compiling code and so on!

What are scripting languages?


What does a script look like?

Declaration of whichinterpreter must be used

comments

Variable assignments These are the actual commands that

the script will executes for you


The OpenDocument Format (ODF) which is the default format

for OpenOffice...

...is nothing else than ZIP archives containing plain text files and

other objects (e.g. images) in normally standard formats

Therefore, it is very easy to create or analyse office texts,

presentations and spreadsheet automatically...

...using the many FOSS tool created just to process plain text

Examples with OpenDocument scripting


Examples (1): Generate OpenDocument invoice

marco => cat my_data.sh INVOICE_DATE='2010/05/15' VENDOR_CODE='007' PO_NUMBER='Purchase Order #1' TOTAL=10 ISSUE=150 DESCRIPTION='Here is your invoice'

1 ASCII data file

+ 35 lines shell script

Result directlyUsable in OpenOffice!


Example (2): Spreadsheets with working graphs and formulas

•Time-of-day BW 1 BW2• Midnight 4.5 6.4• 6.3 6.3• 3.1 6.1• 1.85 5.87

+

Still editable formulas!!!


Example (3):Slideshows drafts from plain text outlines

A: with the same trick used in the spreadsheet example, same scripts complexity

Q: how did I generate the first version of this slideshow?


Other things very easy to do with ODF

Format math formulas and exercises created with Mathematica

Generate course DVDs from existing slideshows

Generate printable versions of multiple choice tests created in

Moodle for online teaching

Automatically import content of spreadsheets or texts to databases

Automatically add watermark or caption to each image in many

texts or presentations

Reduce image resolution, to save disk space

replace company logos or other clipart


Image processing with ImageMagick

The ImageMagick tools (www.imagemagick.org) can be run at the command line or inside a

script to:

Automatically resize all your

pictures

Generate thumbnails for web

publishing

Add captions, frames or

watermarks to them

Example from

www.rubblewebs.co.uk/imagemagic

k/compair.php

http://www.imagemagick.org/


Automatic (collaborative) picture geotagging

Minimap is a

Firefox extension

that lets the user

create lists of

points of interests

and of their

geographical

coordinates


Automatic (collaborative) picture geotagging (2)

The Minimap user needs to know nothing about geotagging or

geographical coordinates at all

1) click on point of interest in Google Maps

2) give it a name and optional description in

the Minimap pop-up window

3) repeat for as many other points as you

like

3) save all place names and coordinates as

ONE plain text file


Automatic, collaborative picture geotagging (3)

Coordinates captured with Minimap can then be automatically inserted inside digital or scanned photographs with the Exiftool utility

Coordinates!


Flow for (collaborative) geotagging

Create plain text listing of place names and their coordinates with Minimap:

Cannigione Harbour: Long: 9.01E, Lat 42.03N

Cannigione Church: Long: 9.04E, Lat 42.06N

...

Create plain text list that associates each picture to a place

picture_1.jpg: Cannigione Harbour

picture_2.jpg: Cannigione Church

picture_3.jpg: Cannigione Harbour

.....


Flow for (collaborative) geotagging (2)

Run one script that:

Reads the two lists

Associates to each picture its coordinates

Tells the exiftools program to write those

coordinates in the EXIF standard format inside

the corresponding JPG file


Advantages of collaborative geotagging

Lists of coordinates must be created only once for

each point of interest

It can be made with Minimap, that is extremely easy

to use and multiplatform, just like Firefox

Being plain text files, lists of coordinates by many

different people can be merged without problems

The person that runs the script can be somebody else


Conclusions: what's the power of scripting?

Computers should save our time, not waste it!

Scripting can save huge amounts of time in all areas of

computer work!

The examples presented are directly relevant and useful in

any school or small business

Scripting automates creation of homework, exercises,

budget reports...


Why is scripting so powerful?

Because it is equivalent to moving from sign language to real

language

We have ten fingers to type on 101 buttons, only one hand to

move one mouse: what's more efficient?

Therefore, scripting makes it much easier to quickly explain to

your computer all you want it to do for you

No matter what you do with computers, there surely is

something that can be automated by scripting


Last but not least...

Even if you're an absolute beginner, there are

thousands of scripting tutorials and practical

examples online

Scripting is multiplatform: while it is already

“built-in” in any Gnu/Linux distribution, the same

scripts can also be run on Windows or Mac systems


Note for Free/Open Source Software activists

Explaining the power of scripting can also be an

effective way to introduce to FOSS many people

that would be intimidated or bored by other

approaches

Did you notice that in all these slides there is NO

mention of: source code, sw licenses etc...?


Resources

ODF scripting

http://freesoftware.zona-m.net/odf-scripting

Collaborative geotagging:

www.tuxradar.com/content/geotagging-linux

www.linux.com/archive/feature/147564

Command line recipes

www.commandlinefu.com

Questions?

For more info: [email protected]

http://www.commandlinefu.com/

The Power of scripting

Technology

digital freedom http

commands marco fioretti

gui vs command line

netmarco fioretti

objectmarco fioretti

foldermarco fioretti

rights reserved2

rights reserved3