These are the dumps from my daily learnings / challenges I faced in my work. hope it helps you too
Friday, November 30, 2007
Mobile banking is on the way?
Mobile based banking services is not a big thing today. All major banks providing mobile facilities to check their account, pay bills and transfer the money from one account in to other.
But the question is about the credibility of such applications. usually the software vendors are providing such mobile softwares to the banks and its customers. and a few banks having their own development team for doing such tasks.
There is a huge market in such mobile based banking software today. if a provider can deliver quality programs with a fool proof security can win the race. but a country like India, is still far behind in using such online applications other than the direct banking.
Millions of mobile users are adding up in every year. and thus the potential for this segment too. but i am doubted about whether we are successful in tapping such an opportunity in a right way.
Once mobile banking catches on,we can make purchases at department stores, supermarkets etc.. To take that next step, phone makers must embed a chip capable of near-field communication (NFC) that will work with special readers in stores, exactly like the contact-less credit and debit cards that are now available.
Vista Sucks ???
When Vista Falls...
I'm a hardcore fan of Microsoft, but they disappointed me with their brand new operating system - Vista!
I tried my best to stick with vista, but every time i have to pay my time and patience for that. many applications are not compatible with vista. and they tried to imitate the GUI functionalities of Linux in to vista, that made it more worse..
My experience with Vista is too horrible! Most popular applications like FileZilla, Y! Messenger and VM Ware workstation is not compatible with Vista. ( Then what the hell they are doing in this great resource consuming monster like vista?, still it remains as a question) . I am getting many such feedbacks from many vista users.
Another comedy is some of the hardware vendors also playing cheap games to support this product. like Compaq laptop series, they are not providing any of the drivers for XP or other Operating systems. but finally i managed to get drivers for my Compaq v3000 series laptop
So Vista & Vista SUCKS !!!
See this wall paper, i got it as a Fwd today, looks very funny...
Thursday, November 22, 2007
What differes in Bourne -Korn and CShell ???
sh | ksh | csh | Meaning/Action |
---|---|---|---|
$ | $ | % | Prompt. |
>! | Force redirection. | ||
>>! | Force append. | ||
> file 2>&1 | > file 2>&1 | >& file | Combine stdout and stderr. |
{ } | Expand elements in list. | ||
` ` | $( ) | ` ` | Substitute output of enclosed command. |
$HOME | $HOME | $home | Home directory. |
~ | ~ | Home directory symbol. | |
var =value | var =value | set var =value | Variable assignment. |
export var | export var =val | setenv var val | Set environment variable. |
${nn } | More than 9 args can be referenced. | ||
"$@" | "$@" | All args as separate words. | |
$# | $# | $#argv | Number of arguments. |
$? | $? | $status | Exit status. |
$! | $! | Background exit status. | |
$- | $- | Current options. | |
. file | . file | source file | Read commands in file . |
alias x =y | alias x y | Name x stands for y . | |
case | case | switch/case | Choose alternatives. |
cd ~- | popd/pushd | Switch directories. | |
done | done | end | End a loop statement. |
esac | esac | endsw | End case or switch . |
exit [n ] | exit [n ] | exit [(expr )] | Exit with a status. |
for/do | for/do | foreach | Loop through variables. |
print -r | glob | Ignore echo escapes. | |
hash | alias -t | hashstat | Display hashed commands (tracked aliases). |
hash cmds | alias -t cmds | rehash | Remember command locations. |
hash -r | unhash | Forget command locations. | |
history | history | List previous commands. | |
r | !! | Redo previous command. | |
r str | !str | Redo command that starts with str . | |
r x =y cmd | !cmd :s/x /y / | Edit command, then execute. | |
if [ $i -eq 5 ] | if ((i==5)) | if ($i==5) | Sample if statement. |
fi | fi | endif | End if statement. |
ulimit | ulimit | limit | Set resource limits. |
pwd | pwd | dirs | Print working directory. |
read | read | $< | Read from terminal. |
trap 2 | trap 2 | onintr | Ignore interrupts. |
unalias | unalias | Remove aliases. | |
until | until | Begin until loop. | |
while/do | while/do | while | Begin while loop. |
Labels:
Bourne shell,
bsh,
csh,
Korn shell,
ksh,
shell command differences
Tuesday, November 20, 2007
“> /dev/null 2>&1″ - What does it mean?
“> /dev/null 2>&1″ - It was one of the weired commands confused me most of the times, when i looked in to the scripts especially, in make files.
It seems some cryptic stuff when you see it for the first time, and unfortunately there is no enough explanations available even in web.
wibble > /dev/null 2>&1Output redirection
The greater-thans (>) in commands like these redirect the program’s output somewhere. In this case, something is being redirected into /dev/null, and something is being redirected into &1.
Standard in, out, and error
There are three standard sources of input and output for a program. Standard input usually comes from the keyboard if it’s an interactive program, or from another program if it’s processing the other program’s output. The program usually prints to standard output, and sometimes prints to standard error. These three file descriptors (you can think of them as “data pipes”) are often called STDIN, STDOUT, and STDERR.
Sometimes they’re not named, they’re numbered! The built-in numberings for them are 0, 1, and 2, in that order. By default, if you don’t name or number one explicitly, you’re talking about STDOUT.
Given that context, you can see the command above is redirecting standard output into /dev/null, which is a place you can dump anything you don’t want (often called the bit-bucket), then redirecting standard error into standard output (you have to put an & in front of the destination when you do this).
The short explanation, therefore, is “all output from this command should be shoved into a black hole.” That’s one good way to make a program be really quiet!
It seems some cryptic stuff when you see it for the first time, and unfortunately there is no enough explanations available even in web.
wibble > /dev/null 2>&1Output redirection
The greater-thans (>) in commands like these redirect the program’s output somewhere. In this case, something is being redirected into /dev/null, and something is being redirected into &1.
Standard in, out, and error
There are three standard sources of input and output for a program. Standard input usually comes from the keyboard if it’s an interactive program, or from another program if it’s processing the other program’s output. The program usually prints to standard output, and sometimes prints to standard error. These three file descriptors (you can think of them as “data pipes”) are often called STDIN, STDOUT, and STDERR.
Sometimes they’re not named, they’re numbered! The built-in numberings for them are 0, 1, and 2, in that order. By default, if you don’t name or number one explicitly, you’re talking about STDOUT.
Given that context, you can see the command above is redirecting standard output into /dev/null, which is a place you can dump anything you don’t want (often called the bit-bucket), then redirecting standard error into standard output (you have to put an & in front of the destination when you do this).
The short explanation, therefore, is “all output from this command should be shoved into a black hole.” That’s one good way to make a program be really quiet!
How to kill a hung process in unix?
You can kill a hung process by giving the command
kill -9 processid
9 is the signal to the process, it allows that process to allow kill itself . remember that you can only kill processes that you have run yourself, otherwise you should have the admin privilege.
kill -9 processid
9 is the signal to the process, it allows that process to allow kill itself . remember that you can only kill processes that you have run yourself, otherwise you should have the admin privilege.
Monday, November 19, 2007
How can you get enough coffe / hot water from your cofffe machine?
Today's learning started form the coffee machine, usually i takes hot water to prepare black tea. and to get a glassful of water, i have to press the button 2 times. they adjusted the machine so that it can fill a half of the cup in a single press. but today i found
Once you pressed the button, the coffee will flow until you release it. regardless of a half cup, or full cup you can get as much coffee as you want!
beware of cron jobs!
my perforce server was yelling like there is no disc space for anymore sync. and just now i came to know that - the cron job which i configured to make the check point in each weekends made this problem...i deleted those files..and it is working now.
so when your machine complaints about the disc space, and you are sure that there was enough space even in the last week..suspect the cron jobs. some of them which scheduled by you may backing up the entire disc ! ( LOL )
so when your machine complaints about the disc space, and you are sure that there was enough space even in the last week..suspect the cron jobs. some of them which scheduled by you may backing up the entire disc ! ( LOL )
Outlook work offline ??
It was todays coolest learning... i am getting so many junk mails now a days, so i decided to create a rule in outlook 2003, but suddenly a message box pop up and it shows like
"You are currently working offline. To use this command, you must go online and connect the Microsoft Exchange Server."
Funny!!! i am using this for last 2 years, and even created so many rules.. what is happening with it now? but i noticed the outlook icon in the system tray bar of outlook express. it appeared in some other way - a red cross symbol upon the normal icon..ALERT !!!
oops, i played around about 10 minutes and finally found that a simple setting can make you mad.
To change the settings, go to Files and un select - Work Offline.
still i didn't have any idea, how it became checked...
Google mobile platform - android
Want to check your disk is full in Unix ???
oops! it happened again... unix machine says, disc is full...more precisely
write: journal: No space left on device
No probelm, command df can save our life.
df shows how much free space is available in each mount.
It has a list of options, and the man page says like
a, --all | include dummy file systems |
-B, --block-size=SIZE | use SIZE-byte blocks |
-h, --human-readable | print sizes in human readable format (e.g., 1K 234M 2G) |
-H, --si | likewise, but use powers of 1000 not 1024 |
-i, --inodes | list inode information instead of block usage |
-k | like --block-size=1K |
-l, --local | limit listing to local file systems |
--no-sync | do not invoke sync before getting usage info (default) |
-P, --portability | use the POSIX output format |
--sync | invoke sync before getting usage info |
-t, --type=TYPE | limit listing to file systems of type TYPE |
-T, --print-type | print file system type |
-x, --exclude-type=TYPE | limit listing to file systems not of type TYPE |
--version | output version information and exit |
But among them, i used df -h. it displays the result in easy to read format. like
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 39G 2.8G 34G 8% /
/dev/hda1 99M 11M 83M 12% /boot
none 254M 0 254M 0% /dev/shm
perforce and chmod
Perforce does not look at your file system to determine if files need to be synced.
It keeps records on the server of everything you've synced.if you have to chmod a file,
you're probably doing something that will get you into trouble later.
if you do stuff without telling perforce, you'll just be swimming against the current
and it will be a lot of trouble Lesson : Don't change the mode of perforce files in your client!
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