Linux Forums - Linux Programming & Scripting

writting a simple UDP server, a little help please?

a_n_h — Fri, 20 Nov 2009 15:36:56 GMT

Hi there,

how are u all doing?

I am writing a simple UDP server, and I have a quick question, I want my server to serve only one client at a time, but I really have no idea where to start, any tips on how to do that, is there a specific function i should use, like for example, connect?

I googled it but to no avail!!

any help is appreciated!!

thank u in advance

simulation using modelsim and xilinx of scripts in fedora linux

gadnet — Fri, 20 Nov 2009 13:09:25 GMT

Gadnet a newbie
Is there anyone ready to assist me? Then cordially let me know what is hindering me from doing this bit of work.
It seems i have not been able to map the files correctly, that which i do not know to do. I will be gratefull if one of the Linux gurus would like to help.
I do not know where the libraries are, this will enable me creat the directory " vlib mti_work and vmap work mti_work"
I do not know where they are so i direct them to my projects or rather copy them to the directory.

-*- mode: compilation; default-directory: "~/projects/transcripts/" -*-
make -k projects/transcripts/compile.do
make: *** No rule to make target `projects/transcripts/compile.do'.
Compilation exited abnormally with code 2

Shell Script for Downloading Images

wizofozz — Fri, 20 Nov 2009 10:57:48 GMT

I am looking to create a shell script to download and image and then go onto the next and download it.

say from . com/family1.jpg it would download that pic and then go onto family2.jpg etc etc.. until there are no more. Any help would be appreciated.

Help with Code:Blocks

Mac_Attack18 — Thu, 19 Nov 2009 18:30:04 GMT

I have tried a few and can't get them to work. I liked code blocks but when i ran my program nothing happened it was the Hello world program they auto generate i just wanted to test it out. There was no output. the program ran and nothing happened.

I am used to Visual Studio where the program is run in the command prompt but nothing happens in Code:Blocks. The program compiles but i don't know if its even run. Code:Blocks had the Intel C++ compiler selected and it couldn't find it so I switched to the GNU compiler. I don't know it that helps

I am not a serious C++ programmer I just like to play around with it.

Will Poll miss events

srinathduraisamy — Thu, 19 Nov 2009 12:31:21 GMT

Hi all,

I have a question.
I have two threads which have two different sets of fds which will be polled using poll( time out = 0 ) system call one thread at a time.
Since no of fds in every thread will be in order of 100.
I just want to know, when an event comes for an fd, will the event for that particular fd will wait till it is being polled.

what are the chances of poll missing the events?. I hope this might have been discussed earlier. If so then can you point me to the correct link. I searched for it but I am not able to find any relevant links.

thanks in advance
srinath.D

bash: change language for scirpt only

chris123a — Thu, 19 Nov 2009 08:40:26 GMT

hi!

I have some problems with a bash-script. e.g. I will find out my ip. I do it with a grep to ifconfig.
but in relation to the systems language my grep will fail because the text between the information differs from language to language (Adresse is german, address in english, .....)

is it possible to change the language for a scipt ONLY that my grep will work on every machine??

thanks!
chris

Number of files that are kept open by a certain process

aryan_ — Thu, 19 Nov 2009 06:45:01 GMT

Hi All,

How can I get the number of files that are kept open by a certain process at a certain time using C++ ?

I want to call the Linux system function that provides me with that information from within C++ source code, for which the number of open files kept open by itself matters to me.

By the way, this C++ source code continuously opens up new files for writing.

Thanks.

cript to tar all files last month and place to another partition

packets — Thu, 19 Nov 2009 06:34:32 GMT

All my user has a directory called backup on each of their home directory. All files was a text file. I want to backup those file after a month had past using tar and delete the file after I tar it.

Here is my some of the command I'm thinking of

Quote:

#!/bin/bash

DATE=`date --date="1 month ago" | awk '{print $2}'`

ls -l /home/user/Maildir/backup/ | grep $DATE | awk '{print $9}' | xargs tar crvf user-200910.tar.gz

I want to apply this command to all my users in the server. I just want to ask some guru in scripting.

Is my script suitable to what I need? Is there any possibility of bottleneck that might cause slow on the server? How can I apply this script to all user's backup dir and each has their own filename?

reading a other users variables

stierenkeutel — Wed, 18 Nov 2009 13:05:05 GMT

Hi,

I'm making a script that change the root password every 12 hours! the idea is: that when a user logged in he need to read first his mail with a new password. The script (that is running as root in cron) sends the mail with the new password by doing
echo "this is the new password: $pasword" |mail -s "password" user
When user opens his mail to have a look to the new password it shows him: "this is the new password: " So it seems that user can't read the variable because itś a variable of root. Is there a way that only a special group of users can't read this variable?

Thanks for your help!

With kind regards

Jerome Kuchler

compiling checkIn.cpp

niketa — Wed, 18 Nov 2009 11:45:27 GMT

Hi there,
I am compiling checkIn.cpp using g++ and it's giving following error. Pls help..

checkin.cpp:5:18: error: stdlib: No such file or directory
checkin.cpp: In function 'int main()':
checkin.cpp:10: error: 'queue' was not declared in this scope
checkin.cpp:10: error: 'string' was not declared in this scope
checkin.cpp:10: error: 'q' was not declared in this scope
checkin.cpp:14: error: 'ifstream' was not declared in this scope
checkin.cpp:14: error: expected `;' before 'fin'
checkin.cpp:16: error: 'fin' was not declared in this scope
checkin.cpp:19: error: 'cout' was not declared in this scope
checkin.cpp:19: error: 'endl' was not declared in this scope
checkin.cpp:41: error: 'cout' was not declared in this scope
checkin.cpp:46: error: 'cout' was not declared in this scope
checkin.cpp:51: error: 'cout' was not declared in this scope
checkin.cpp:58: error: 'cout' was not declared in this scope
checkin.cpp:63: error: 'cout' was not declared in this scope
checkin.cpp:66: error: 'endl' was not declared in this scope
checkin.cpp:72: error: 'endl' was not declared in this scope
checkin.cpp:78: error: 'endl' was not declared in this scope

ANSI C Pre-processor - how to use constant suffix?

xyz000 — Wed, 18 Nov 2009 11:18:58 GMT

Hi,

Suppose I have some code like this:

Code:

const unsigned int = 0x1234abcdU;

I want to achieve this with a macro. Something like:

Code:

const unsigned int = CREATE_UINT(0x1234, 0xabcd);

Optimistically I tried this:

Code:

#define CREATE_UINT(a,b) ((a << 16) | (b))U

The problem is that the "U" won't compile because of the brackets in the macro definition. I've tried many combinations of adding/removing brackets and of putting the U elsewhere but I still can't define a valid macro. Any ideas for a solution?

Thanks.

large number of simultaneous open files

aryan_ — Wed, 18 Nov 2009 10:43:35 GMT

Hi All,

I know that there is an OS limitation on the number of files that can be kept open for writing simultaneously.

However, I want to somehow overcome this limitation.

Let's say, if I have to process X number of files simultaneously at a certain time, where X is greater than the number of simultaneously open files that OS can handle, it seems to be the only solution to close the oldest files which were opened before any others first, and open the new ones instead.

Maybe a circular buffer or something similar is needed for this.

What is the best way to handle such a scenario in Linux using C++ ?

What Linux system function gives me the number of files that I can keep open at a certain time ?

Thanks.

Can't locate MIME::Lite.pm in @INC

pu8y — Wed, 18 Nov 2009 07:38:08 GMT

Hi all,

I am new in Perl language. I wrote a perl script to send an email notification to users by using:

use MIME::Lite;

However, i get the error:
Can't locate MIME Lite.pm in @INC(@INC contains: /usr/lib/perl5/5.10.0/i386-linux-thread-multi /usr/lib/perl5/5.10.0 /usr/local/lib/perl5/site_perl/5.10.0/i386-linux-thread-multi /usr/local/lib/perl5/site_perl/5.10.0 /usr/lib/perl5/vendor_perl/5.10.0/i386-linux-thread-multi /usr/lib/perl5/vendor_perl/5.10.0 /usr/lib/perl5/vendor_perl /usr/local/lib/perl5/site_perl .) at email.pl line 5.
BEGIN failed--compilation aborted at email.pl line 5.

Below is the simplify version for my code. What 's wrong with my coding?

Code:

my $message = MIME::Lite->new(

To => 'xxx@mail.com',

Subject => 'message',

Data => 'Message body'

);

$message->send();

[SOLVED] sometimes works, sometimes doesn't !?

clickalot — Tue, 17 Nov 2009 21:34:34 GMT

his,

this is some quirk or something.

i have this line in a bash script:

Code:

cat $sortfile | sort -nr > $sortfile

$sortfile is some text file with lines like:number.some_text ...

i don't understand why this works erratically...

i changed to:

Code:

cat $sortfile | sort -nr > $sortfile-2

and now it seems ok

what should i be learning here?...

Missing argument to -exec

R_Winston — Mon, 16 Nov 2009 20:45:40 GMT

I was wondering if anyone could explain what is wrong with this. I keep getting a missing argument to `-exec'

find /data/shippers -name "*.txt" -mtime 2 -type f -exec tar czvf $1.$(date +%y%m%d-%H%M%S).tar /data/shippers/archive

What I am trying to do is find all the txt files that are 2 to 3 days old and archiving them into the archive folder. Any advice or help would be greatly appreciated.

Thank You in advance

Winston