Techpsyche's Tech blog!!!

Lokesh MD's official technoblog

Apple iPad2

After resisting a lot and also managing for several days I finally decided to buy an iPad 2. Though there was no necessity or urgency I still wanted to try my hands on this gadget since it would definitely be handy during my travel. I decided for iPad since none of the tablets I tried in store attracted me, either with looks or with features, to buy them. Also recently I was forced to go back to iPhone after having to try blackberry torch for 4 months. One thing I will have to admit about apple products is that they are made keeping in mind the ease of use and also to cater to various age group. They are really easy to use and deliver as promised.
Ok, now talking about the iPads, it’s something that anybody would fall in love at the first instance. Initially I had thought it’s no big deal since it’s nothing but a enlarged version of iPhone 4 but I was wrong. It does matter when you read news on a bigger screen, when you post blogs like this, when you view photos, watch videos and so on. The iPad 2 comes with a front camera which will really help you when video chatting via a tablet. It also comes with a faster multimedia chip that betters the performance. however there are some drawbacks of it too such as every thing will have to be synced thru iTunes, no USB, etc. However given the user experience and the number of apps the store has to offer the iPad will surely beat any other tablet in the market. It’s tough to find one in the store since the recent Japan earthquake has affected the production of some iPad parts. I am hoping that they will overcome this and have more in the market soon.

2 May 2011 at 18:11 - Comments

Top 10 iPhone app for travellers.

I travel quite often and have found these apps very handy on my iPhone.

  • Google Maps
  • Flight Tracker
  • Page one Assistant
  • The Weather Channel
  • iTranslator
  • Camera
  • Extra-Charge
  • Converter
  • Yelp
  • Alarm Clock
8 January 2010 at 20:52 - Comments

Vi Commands

Simple Commands of the vi Editor

ESC Changes to last line mode.
i Changes to insert mode (characters appear at the current cursor position).
a Changes to insert mode (characters appear after the current cursor position).
A Changes to insert mode (characters are added at the end of the line).
R Changes to command mode (overwrites the old text).
r Changes to insert mode and overwrites each character.
s Changes to insert mode (the character where the cursor is positioned is replaced by the next entry you make).
C Changes to insert mode (the rest of the line is replaced by the new text).
o Changes to insert mode (a new line is inserted following the current one).
O Changes to insert mode (a new line is inserted preceding the current one).
x Deletes the current character.
dd Deletes the current line.
dw Deletes up to the end of the current word.
cw Changes to insert mode (the rest of the current word is overwritten by the next entries you make).
u Undoes the last command.
J Joins the following line with the current one.
. Repeats the last command.
: Changes to last line mode.

Complex Commands of the vi Editor

:q! exits vi without saving any changes
:w filename saves as filename
:x saves the modified file and exits the editor
:e filename edits (loads) filename
:u undoes the last edit command
5 July 2009 at 00:22 - Comments

Important bash commands

alias    Create an alias

apropos  Search Help manual pages (man -k)

apt-get  Search for and install software packages (Debian)

aspell   Spell Checker

awk      Find and Replace text, database sort/validate/index

bash     GNU Bourne-Again SHell

bc       Arbitrary precision calculator language

bg       Send to background

break    Exit from a loop

builtin  Run a shell builtin

bzip2    Compress or decompress named file(s)

cal      Display a calendar

case     Conditionally perform a command

cat      Display the contents of a file

cd       Change Directory

cfdisk   Partition table manipulator for Linux

chgrp    Change group ownership

chmod    Change access permissions

chown    Change file owner and group

chroot   Run a command with a different root directory

chkconfig System services (runlevel)

cksum    Print CRC checksum and byte counts

clear    Clear terminal screen

cmp      Compare two files

comm     Compare two sorted files line by line

command  Run a command – ignoring shell functions

continue Resume the next iteration of a loop

cp       Copy one or more files to another location

cron     Daemon to execute scheduled commands

crontab  Schedule a command to run at a later time

csplit   Split a file into context-determined pieces

cut      Divide a file into several parts

date     Display or change the date & time

dc       Desk Calculator

dd       Convert and copy a file, write disk headers, boot records

ddrescue Data recovery tool

declare  Declare variables and give them attributes

df       Display free disk space

diff     Display the differences between two files

diff3    Show differences among three files

dig      DNS lookup

dir      Briefly list directory contents

dircolors Colour setup for `ls’

dirname  Convert a full pathname to just a path

dirs     Display list of remembered directories

dmesg    Print kernel & driver messages

du       Estimate file space usage

echo     Display message on screen

egrep    Search file(s) for lines that match an extended expression

eject    Eject removable media

enable   Enable and disable builtin shell commands

env      Environment variables

ethtool  Ethernet card settings

eval     Evaluate several commands/arguments

exec     Execute a command

exit     Exit the shell

expect   Automate arbitrary applications accessed over a terminal

expand   Convert tabs to spaces

export   Set an environment variable

expr     Evaluate expressions

false    Do nothing, unsuccessfully

fdformat Low-level format a floppy disk

fdisk    Partition table manipulator for Linux

fg       Send job to foreground

fgrep    Search file(s) for lines that match a fixed string

file     Determine file type

find     Search for files that meet a desired criteria

fmt      Reformat paragraph text

fold     Wrap text to fit a specified width.

for      Expand words, and execute commands

format   Format disks or tapes

free     Display memory usage

fsck     File system consistency check and repair

ftp      File Transfer Protocol

function Define Function Macros

fuser    Identify/kill the process that is accessing a file

gawk     Find and Replace text within file(s)

getopts  Parse positional parameters

grep     Search file(s) for lines that match a given pattern

groups   Print group names a user is in

gzip     Compress or decompress named file(s)

hash     Remember the full pathname of a name argument

head     Output the first part of file(s)

history  Command History

hostname Print or set system name

id       Print user and group id’s

if       Conditionally perform a command

ifconfig Configure a network interface

ifdown   Stop a network interface

ifup     Start a network interface up

import   Capture an X server screen and save the image to file

install  Copy files and set attributes

join     Join lines on a common field

kill     Stop a process from running

killall  Kill processes by name

less     Display output one screen at a time

let      Perform arithmetic on shell variables

ln       Make links between files

local    Create variables

locate   Find files

logname  Print current login name

logout   Exit a login shell

look     Display lines beginning with a given string

lpc      Line printer control program

lpr      Off line print

lprint   Print a file

lprintd  Abort a print job

lprintq  List the print queue

lprm     Remove jobs from the print queue

ls       List information about file(s)

lsof     List open files

make     Recompile a group of programs

man      Help manual

mkdir    Create new folder(s)

mkfifo   Make FIFOs (named pipes)

mkisofs  Create an hybrid ISO9660/JOLIET/HFS filesystem

mknod    Make block or character special files

more     Display output one screen at a time

mount    Mount a file system

mtools   Manipulate MS-DOS files

mv       Move or rename files or directories

mmv      Mass Move and rename (files)

netstat  Networking information

nice     Set the priority of a command or job

nl       Number lines and write files

nohup    Run a command immune to hangups

nslookup Query Internet name servers interactively

open     Open a file in its default application

op       Operator access

passwd   Modify a user password

paste    Merge lines of files

pathchk  Check file name portability

ping     Test a network connection

pkill    Stop processes from running

popd     Restore the previous value of the current directory

pr       Prepare files for printing

printcap Printer capability database

printenv Print environment variables

printf   Format and print data

ps       Process status

pushd    Save and then change the current directory

pwd      Print Working Directory

quota    Display disk usage and limits

quotacheck Scan a file system for disk usage

quotactl Set disk quotas

ram      ram disk device

rcp      Copy files between two machines

read     read a line from standard input

readonly Mark variables/functions as readonly

reboot   Reboot the system

renice   Alter priority of running processes

remsync  Synchronize remote files via email

return   Exit a shell function

rev      Reverse lines of a file

rm       Remove files

rmdir    Remove folder(s)

rsync    Remote file copy (Synchronize file trees)

screen   Multiplex terminal, run remote shells via ssh

scp      Secure copy (remote file copy)

sdiff    Merge two files interactively

sed      Stream Editor

select   Accept keyboard input

seq      Print numeric sequences

set      Manipulate shell variables and functions

sftp     Secure File Transfer Program

shift    Shift positional parameters

shopt    Shell Options

shutdown Shutdown or restart linux

sleep    Delay for a specified time

slocate  Find files

sort     Sort text files

source   Run commands from a file `.’

split    Split a file into fixed-size pieces

ssh      Secure Shell client (remote login program)

strace   Trace system calls and signals

su       Substitute user identity

sudo     Execute a command as another user

sum      Print a checksum for a file

symlink  Make a new name for a file

sync     Synchronize data on disk with memory

tail     Output the last part of files

tar      Tape ARchiver

tee      Redirect output to multiple files

test     Evaluate a conditional expression

time     Measure Program running time

times    User and system times

touch    Change file timestamps

top      List processes running on the system

traceroute Trace Route to Host

trap     Run a command when a signal is set(bourne)

tr       Translate, squeeze, and/or delete characters

true     Do nothing, successfully

tsort    Topological sort

tty      Print filename of terminal on stdin

type     Describe a command

ulimit   Limit user resources

umask    Users file creation mask

umount   Unmount a device

unalias  Remove an alias

uname    Print system information

unexpand Convert spaces to tabs

uniq     Uniquify files

units    Convert units from one scale to another

unset    Remove variable or function names

unshar   Unpack shell archive scripts

until    Execute commands (until error)

useradd  Create new user account

usermod  Modify user account

users    List users currently logged in

uuencode Encode a binary file

uudecode Decode a file created by uuencode

v        Verbosely list directory contents (`ls -l -b’)

vdir     Verbosely list directory contents (`ls -l -b’)

vi       Text Editor

vmstat   Report virtual memory statistics


watch    Execute/display a program periodically

wc       Print byte, word, and line counts

whereis  Report all known instances of a command

which    Locate a program file in the user’s path.

while    Execute commands

who      Print all usernames currently logged in

whoami   Print the current user id and name (`id -un’)

Wget     Retrieve web pages or files via HTTP, HTTPS or FTP

write    Send a message to another user

xargs    Execute utility, passing constructed argument list(s)

yes      Print a string until interrupted

.        Run a command script in the current shell

###      Comment / Remark

5 July 2009 at 00:14 - Comments

Hardware Vs Software

Often I wonder why does the improvement in hardware leads to enhancements in software and vice-versa which will end up in a kind of race between the two. This also adds onto my curiosity as to where this race would end???????

When I started using computers there was this 486/586 machines with 32mb ram which ran command line softwares like DOS,fortran, pascal,etc. As and when the time proceeded slowly graphical user interface came into picture with the introduction of win95 this demanded the hardware to be upgraded and the saga continued like this and today here I am using Operating system like vista and ubuntu 9.0 which demands 4gb of ram and p4 processors and yet I feel the cravings for hardware by software and vice-versa is growing. I would rather say we should change the chicken and egg proverb to hardware-software proverb….

Having said that I am hereby posting my first blogpost on my technoblog. I shall promise you all that I shall be sharing some useful and interesting technical topics here.

3 July 2009 at 08:18 - Comments