New SS - *The Dearest Buddies* (Part 11 and 12 DONE - Pg 28) - Page 13

--9:50 am : KVRL logged in and experimenting the software...Each at their respective seats... KV next to each other... RL across them... (RSS- Required Synchronized Session)--

Vishnu: Idhu semma matter machaan...

Karthik: Hmm... What? Have u never attended a RSS before?

Vishnu: No not like that... This is a whole lot professional than the college ones...

Karthik: Hmm Yeah that is true...More comfortable as well...

Vishnu: Eppadi solre?

Karthik: In this...u don't have to utilize the Webcam and u can mute the microphone while listening... This will keep the session at high-speed and there is a chatting box for the joinees of this RSS...

Vishnu: Ohoo... Hmm.. Cool that will make it high quality... Great...

Raji: It has been 6 months since the last synchronized session we had in college...

Lakshmi: Oh yeah! Those ones would buffer so much because of every1 logged in Webcam and Microphone.. Also all were being more self conscious than being attentive of the class...

Raji: (Giggles) I know... Those professors faces! In class so pleasant.. In RSS so gingerly...

Lakshmi: (Sighs) Let's see how this works...

--K texts R while waiting...--

--VL talk thru the personal chat in the RSS software...--

--KVRL dads join the RSS with Mr. Hall... They r the moderators of this session...Everyone turns on their microphones to greet--

K dad: Welcome Guys!

Raji: Morning Uncle...

Vishnu: Hello...

Lakshmi: Bonjour

Karthik: GM

V dad: Okay guys... Any predictions on what this RRS will be about?

Lakshmi: Does it have to do with individual training...or a subject familiarization session?

R dad: Subject... Our sessions will be only review and familiarization of what you had learnt in college... How to apply them here... The last few RSS will be for handling the company...

Vishnu: Alright... So what are we tackling today?

Mr. Hall: Shell Scripting...

Karthik: Oh... We never really learnt it in depth...

L dad: That is what this session is for... Let's start with a quote... Look into your Chatbox... U may turn off ur microphone... Just listen and comprehend... Ask questions in the Chatbox.. One of us will answer...

--Session starts...Microphones switched off...(Chatting stuff will be indented)--

Karthik: Interesting...

Vishnu: So many languages! (K laughs)

R dad: Okay guys... R u able to see the presentation? And hear us?

V dad: Alright... So we will be going through the presentation with you... If you have any questions, feel free to enter in the Chatbox... Or click the "raise your hand" button...This will let us know that you r willing to talk.. Then we will stop at a round place and answer ur Q...

--(Presentation stuff will be italicized)--

Advanced Bash-Scripting Guide

• Resource-intensive tasks, especially where speed is a factor (sorting, hashing, recursion [2] ...)

• Procedures involving heavy-duty math operations, especially floating point arithmetic, arbitrary precision calculations, or complex numbers (use C++ or FORTRAN instead)

• Cross-platform portability required (use C or Java instead)

• Complex applications, where structured programming is a necessity (type-checking of variables, function prototypes, etc.)

• Mission-critical applications upon which you are betting the future of the company

• Situations where security is important, where you need to guarantee the integrity of your system and protect against intrusion, cracking, and vandalism

• Project consists of subcomponents with interlocking dependencies

• Extensive file operations required (Bash is limited to serial file access, and that only in a particularly clumsy and inefficient line-by-line fashion.)

• Need native support for multi-dimensional arrays

• Need data structures, such as linked lists or trees

• Need to generate / manipulate graphics or GUIs

• Need direct access to system hardware or external peripherals

• Need port or socket I/O

• Need to use libraries or interface with legacy code

• Proprietary, closed-source applications (Shell scripts put the source code right out in the open for all the world to see.)

R dad: Firstly, do you guys remember all this info? (KVRL click the thumbs-up symbol)...

K dad: Great... So a brief explanation for that...

V dad: If any of the above applies, consider a more powerful scripting language -- perhaps Perl, Tcl, Python, Ruby -- or possibly a compiled language such as C, C++, or Java. Even then, prototyping the application as a shell script might still be a useful development step.

L dad: What follows is a tutorial on shell scripting. It relies heavily on examples to illustrate various features of the shell. The example scripts work -- they've been tested, insofar as possible -- and some of them are even useful in real life. You can play with the actual working code of the examples in the source archive (scriptname.sh or scriptname.bash), give them execute permission (chmod u+rx scriptname), then run them to see what happens. Should the source archive not be available, then cut-and-paste from the HTML or pdf rendered versions. Be aware that some of the scripts presented here introduce features before they are explained.

Example 2-1. cleanup: A script to clean up log files in /var/log

# Cleanup

# Run as root, of course.

cd /var/log

cat /dev/null > messages

cat /dev/null > wtmp

echo "Log files cleaned up."

R dad: There is nothing unusual here, only a set of commands that could just as easily have been invoked one by one from the command-line on the console or in a terminal window. The advantages of placing the commands in a script go far beyond not having to retype them time and again. The script becomes a program -- a tool -- and it can easily be modified or customized for a particular application.

Example 2-2. cleanup: An improved clean-up script

#!/bin/bash

# Proper header for a Bash script.

# Cleanup, version 2

# Run as root, of course.

# Insert code here to print error message and exit if not root.

LOG_DIR=/var/log

# Variables are better than hard-coded values.

cd $LOG_DIR

cat /dev/null > messages

cat /dev/null > wtmp

echo "Logs cleaned up."

exit # The right and proper method of "exiting" from a script.

# A bare "exit" (no parameter) returns the exit status

#+ of the preceding command.

R dad: Now that's beginning to look like a real script. But we can go even farther . . .

Example 2-3. cleanup: An enhanced and generalized version of above scripts.

# -LOG_DIR=/var/log

ROOT_UID=0 # Only users with $UID 0 have root privileges.

LINES=50 # Default number of lines saved.

E_XCD=86 # Can't change directory?

E_NOTROOT=87 # Non-root exit error.

# Run as root, of course.

if [ "$UID" -ne "$ROOT_UID" ]

then

echo "Must be root to run this script."

exit $E_NOTROOT

fi

if [ -n "$1" ]

# Test whether command-line argument is present (non-empty).

then

lines=$1

else

lines=$LINES # Default, if not specified on command-line.

fi

# Stephane Chazelas suggests the following,

#+ as a better way of checking command-line arguments,

#+ but this is still a bit advanced for this stage of the tutorial.

#

# E_WRONGARGS=85 # Non-numerical argument (bad argument format).

#

# case "$1" in

# "" ) lines=50;;

# *[!0-9]*) echo "Usage: 'basename $0' lines-to-cleanup";

# exit $E_WRONGARGS;;

# * ) lines=$1;;

# esac

#

#* Skip ahead to "Loops" chapter to decipher all this.

cd $LOG_DIR

if [ 'pwd' != "$LOG_DIR" ] # or if [ "$PWD" != "$LOG_DIR" ]

# Not in /var/log?

then

echo "Can't change to $LOG_DIR."

exit $E_XCD

# cd /var/log || {

# echo "Cannot change to necessary directory." >&2

# exit $E_XCD;

tail -n $lines messages > mesg.temp # Save last section of message log file.

mv mesg.temp messages # Rename it as system log file.

# cat /dev/null > messages

#* No longer needed, as the above method is safer.

cat /dev/null > wtmp # ': > wtmp' and '> wtmp' have the same effect.

echo "Log files cleaned up."

# Note that there are other log files in /var/log not affected

#+ by this script.

exit 0

# A zero return value from the script upon exit indicates success

#+ to the shell.

R dad: Since you may not wish to wipe out the entire system log, this version of the script keeps the last section of the message log intact. You will constantly discover ways of fine-tuning previously written scripts for increased effectiveness. Any questions?

--KVRL all click the "raise hand" button and turn on their microphones--

K dad: Uh.. Okay.. First Lakshmi...

Lakshmi: Okay so these examples are effective for us to comprehend... Will it be alright to save the Presentation or does it have to be cited before doing that?

L dad: Of course it has to be cited... Or it will be plagiarism...

Lakshmi: Thank u...(Turns off her microphone(MP))

K dad: Raji?
Raji: Just to make sure.. Bash is the acronym for "Bourne-Again shell" right? (Turns off MP)

K dad: Yup... Karthik?

Karthik: What is the point of being familiarized with the complexity of the commands?

V dad: Good Question... U have to in order to get the best output of your work and for u to conduct further sessions for the employees... When u teach, always teach all the methods from simple to complex...Vishnu?

Karthik: Thanks (Turns off MP)

Vishnu: Is meta-meaning and special characters unit coming..or did u assume that we should have learnt it already...

R dad: U should have and should be familiarized with it by now as well...

Vishnu: Thank u

--Session continues...Presentation goes on...--

Vishnu: Enna machaan idhu? They r giving us homework?

K dad: Vishnu will u please turn your microphone off?

Vishnu: (Realizes) Oh sorry... (Turns MP off)

KRL: (Giggle hard)

Vishnu: Seriously guys? Wow... What good friends I have...

Karthik: Just think about Mr. Hall... He wouldn't have understood anything u said...(Laughs)

Vishnu: (Glares at K) Concentrate!

--The long presentation is finally over...KVRL at the Cafeteria...--

Karthik: Habbahh... So long...

Lakshmi: It was boring..but more interesting than the college ones...

Raji: Oh yeah... Freddy? Can u come here please?

Freddy: Hello... What would u like to have today?

Vishnu: Bonjour Freddy.. I would like a cup of green tea please...

Karthik: How about latte for me?

Freddy: Sure and u two?

Lakshmi: Cappuccino

Raji: Green tea... Thanks!

Freddy: Mhm.. My pleasure... R u sure you guys don't want lunch? It is 1:17pm

Karthik: No way! We just came from a LONG RSS... If we eat...then we will sleep...

Vishnu: Oh yeah... Then think about the trouble we would get in...

Freddy: (Laughs) Okay as u wish.. any cookies or...??

Lakshmi: Oh sure... I want Striped Icebox Cookies that are caramel glazed...YUM!

Raji: (Giggles) How about a donut that is glazed with blueberry coated sugar syrup?

Vishnu: For me...Chocolate chip cookies that are cinnamon spread with strawberry syrup...

Karthik: Finally! I would like... French Toast honey glazed with vanilla coating...

Freddy: Wow...U guys have very good tastes... Will be back with all u asked for...

Vishnu: Thanks Freddy...

--KVRL enjoy their mini snack meal... Mr. Hall came by and told them to head home--

Vishnu: What is this? I would have had a full meal of lunch!

Karthik: Cha...Sari Vidu da...

Lakshmi: (Sighs) I was in the mood for an Italian soup...

Raji: Well... What r we going to do here then? Let's leave...

Vishnu: Okay... Karthi? Nee innakku drive pannudaa...

Karthik: Sure daa! (Smiles)

--KVRL at home... Everyone in casuals now...--

Lakshmi: Vishnu? Innaikku Alps la 40 degrees fahrenheit irruku daa... Let's go there please?

Vishnu: (Sighs) Well... I guess... I mean it would be refreshing...

Karthik: I am not coming... I gotta go to the airport to pick up Albert...

Raji: I am soo tired... I only got four hours of sleep last night... Am going to take a nap...

Lakshmi: Hmm... Sari Vishnu namba polaamaa?

Vishnu: Well it is 2:30pm... We can be back for dinner...Sufficient time... Okay?

Lakshmi: Thank u! U r the best Vish!!

Vishnu: Gonna change? Or coming like that?

Lakshmi: Changing... U too right? Wear a mountain outfit...

Vishnu: Mmm... Okay... U might need your scarf...

Lakshmi: Oh yeah... Thanks for reminding me...

--VL look perfect for going to the mountains...In the car--

Lakshmi: Thanks Vish...

Vishnu: Edhukku?

Lakshmi: For taking me to the Alps...

Vishnu: No probs...

Lakshmi: R u tired?

Vishnu: No not at all! I am as excited as u!!

Lakshmi: (Smiles) Great... Let's have fun!

-- The Alps... Chilly... Strong winds... Snow patches here and there... Best place for hiking... Dry blow... Very pleasant... Slow teeth chattering... Goosebumps... Mild shivering... Comfy gloves... Boots the best for your feet and legs... Serene outlook... Refreshing... --

--VL walk from the car in the parking lot...--

Vishnu: Ey please don't make any mischief here...

Lakshmi: (Gives a disregarding look) Podaa

Vishnu: What? appo r u gonna do something?

Lakshmi: Nothing planned...But probably...

Vishnu: Oh my gosh (Shocked) NOOO! Karthik Raji vera inga illai... I don't want to be the victim here... Please Laksh!! (Pleading Face)

Lakshmi: Paakalaam Vishnu...

Vishnu: (Under his breath) Innaikku either she will empty my wallet or embarass me... Hopefully not both!! (Sighs)

Lakshmi: Enna? I couldn't hear...

Vishnu: Nothing... Please!

Lakshmi: (Giggles)

Vishnu: (Murmurs again) Idhukku onum koraichal illai...

Lakshmi: Stop talking under your breath and share with me as well...

Vishnu: Onnum illai... Vidu... Sari..please be a good girl?

Lakshmi: Ok-- (Spots something and thinks) Maybe not... (Continues walking...)

Vishnu: What? I am returning if u do anything...

Lakshmi: Po I don't care... I will make you come back somehow...

Vishnu: Cha... Fine Fine... I will make up my mind...

Lakshmi: Adhu... Come on... you know me...

Vishnu: (Laughs finally) Sari Sari...

-- A HUGE wind storm comes through --

Lakshmi: (Hugs V...Shivering) I am cold

Vishnu: Hold on for a few mins... I thought u said the weather was good today here...

Lakshmi: Two hours ago it said the weather was good... Check again

Vishnu: Okay...(Takes out his phone to open the weather app) Pch... No reception here...

Lakshmi: Uh go over there... Near that tower... (Points to a signal tower)

Vishnu: (Goes there...) Oh (Comes back)

Lakshmi: Ennadaa?

Vishnu: There is a blizzard in Cannes... So Marseille will have its effects...Only strong winds though.. The temperature is still the same...

Lakshmi: Yesss!!!! Amazing Vishnu!!

Vishnu: Hey it will be chilly... We should get back home...

Lakshmi: Of course not... We are going to hike... See how many people are here.. It will be fun please Vish??

Vishnu: (Smiles) Hmm okay... Vaa Lets go to the booth and get the tickets and stuff to hike.

--VL buy the tickets and start their hike in the trail with the hiking sticks...--

Lakshmi: These winds are also a form of pleasure...

Vishnu: (Mindvoice- Solluva maa nee... Ppahh enna kuliruu... Watch one of us getting sick tomorrow... Pleasure huh? At least it is Friday today...)

Lakshmi: Lengthy mind voice oh?

Vishnu: Illai nothing like that...

Lakshmi: Nambittom... Edhavadhu interesting ah pannudaa... U r so boring...

Vishnu: (Mindvoice - Endha situation la enna kekkure? Haiyoo ippove kannakattuthee...)

Lakshmi: Stop your own little chit chatting Vishnu... It is irritating...

Vishnu: Lakshmi... I am cold...

Lakshmi: 40 degrees kke u r cold?

Vishnu: If it was 40 C... then I would be sweating... but it is 40 F! It is cold...

Lakshmi: I agree but that is the thrill...

Vishnu: Apparom... I brought u here... so... (Gives a sneaky smile)

Lakshmi: Enna? (Doubtful look)

Vishnu: How about a hug? Please?

Lakshmi: How about a push? Right now?

Vishnu: Hey... Adhellam pannidadhaa... We are hiking in the mountains! (Shocked)

Lakshmi: (Laughs) I was kidding... Here... (Gives V a warm hug)

Vishnu: U scared me for my life in a second... Oh gosh!

Lakshmi: (Laughs) See? Now that was a little interesting for me...

Vishnu: How come danger and trouble interests you so much?

Lakshmi: Adhu appadithaan... (Smiles)

Vishnu: (Watches the sky while walking)

Lakshmi: Ouch! Idiot! Pch...(Scrunches face)

Vishnu: Enna?

Lakshmi: Watch where u place the hiking stick... Don't place it on my foot!

Vishnu: I did? Oh... Sorry... The sky is beautiful...

Lakshmi: (Smiles)

--V Talks with another hiker and walks forward...L behind--

Hiker: Bounjour!

Vishnu: Salut... Comment allez-vous?

Hiker: Je vais bien, et vous?

Vishnu: Bien, merci...

Hiker: Uh do you know Spanish? I am actually from Spain... I only know a little of French and English...

Vishnu: Oh yes I do... Yo soy Vishnu...

Hiker: Me llamo Abilio

Vishnu: Dnde vives?

Hiker: Vivo in Bercelona... Y t?

Vishnu: Marseille...pero yo soy Indian...

Hiker: Okay...

Vishnu: Por qu ests aqu?

Hiker: por la fotografa

Vishnu: Yo soy fotgrafo tambin...

-- For another half a mile V and the hiker talk about photography since both are photographers... then... V goes back to L--

Vishnu: Hola! Qu ests haciendo?

Lakshmi: Estoy caminando...

Vishnu: Do u want to return now?

Lakshmi: R u kidding? It has only been 45 minutes since we arrived!

Vishnu: Hehe... Angaa coffee shop irrukku paar... Do u want cappuccino?

Lakshmi: Please Vish! Thank uuu!!

Vishnu: Wait here... I will get two cups...

--V is standing in the line... L leans on the hiking sticks admiring V--

Hiker: Hola... Yo soy Abilio... R u his friend? (Points to V)

Lakshmi: (Nods) Hola... Cmo ests?

Hiker: Muy bien... Lo entiendes espaol?

Lakshmi: S...

Hiker: (Points to V) l es muy kind... sweet guy...

Lakshmi: (Smiles) Gracias!

Hiker: If u don't mind... Can I ask u something?

Lakshmi: Seguro... Sure...

--V comes back and hands one cup to L--

Hiker: R u his girlfriend?

Vishnu: Uh well w--

Lakshmi: Yeah... (VL smile for a split second)

Hiker: Very cute couple... Tengo que salir...

VL: Adis!

--VL slowly sip their coffee...But relish each other's looks than the taste... --

Vishnu: Why did you say like that?

Lakshmi: Like what?

Vishnu: To Abilio...

Lakshmi: (Smiles) What to Abilio?

Vishnu: That you are my g--

Lakshmi: Hey stop... U r making me feel shy... (Blushes)

Vishnu: (Admires her face that has a cute blush and watery eyes because of the strong winds blowing against her...)

Lakshmi: Vishnu... Stop... Its really awkward...

Vishnu: I don't care! I am looking at my g--

Lakshmi: (Smiles) Shut up...

Vishnu: (Teasing look) And if I don't?

Lakshmi: How about a push? To your left?

Vishnu: (Looks at his left side) OMG! I will fall off the cliff... Then die... (Shocked)

Lakshmi: Appo pesama coffee kudii please...

Vishnu: (Sighs) I am cold...

--After like another hour of hiking... L plans something...--

Lakshmi: Vish? Give me your phone please? And will u go there? To that booth and get the hiking guides? Take your own time... (She sits down -- Looks excited)

Vishnu: Why are u hyper?

Lakshmi: Uh no nope.. Nothing.. Maybe the coffee...(Tries to hide her smile)

Vishnu: Hmm... Something fishy... (Walks away)

Lakshmi: (Murmurs) Oh God Please... Don't get me in trouble... I taking a risk for a sense of thrill !! Please Please... Pch Vidu Laksh! U will me fine! Unnakku risk edukaradhu ellam rusk saapidraa maadhiri... Have fun! (Smiles) I am nervous yet excited!! (Shivers)

*What will Lakshmi do for her sake of fun? Guess guys!*

--Part 8 on the way--

Friends - I am looking forward for your feedback!