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LD_Library_Path

Himanshu Thappa [himanshut at KPITCummins.com]
Sat, 16 Sep 2006 02:10:33 +0530

Hi James

Plz tell me what LD_Library_path does?tel me asap.

With Regards

Himanshu Thappa
Architecture Engineer
KPIT Cummins GBS Ltd.
Ext No. 5648
Mob. 09881407689


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Lew Pitcher [lpitcher at sympatico.ca]
Fri, 15 Sep 2006 17:32:53 -0400

On Friday 15 September 2006 16:40, Himanshu Thappa wrote:

> Hi James 

Hi, Himanshu

I'm not James, but I might be able to answer your question.

> Plz tell me what LD_Library_path does?

LD_Library_path doesn't do anything. Primarily because what you are looking for isn't called "LD_Library_path". Instead, you want LD_LIBRARY_PATH

LD_LIBRARY_PATH is the name of an environment variable that you can set before running a program. If your program is not a "setuid" or "setgid" program, the Linux program loader will first look in the directories named by the LD_LIBRARY_PATH environment variable for any shared object libraries that the program needs. If it finds the needed library there, it uses it. Otherwise, it continues to search in all the "regular" places until it either finds the library or it gives up.

LD_LIBRARY_PATH is commonly used to override the shared object search paths, so that you can give the program a replacement for one of the standard libraries, or to give the program a library that hasn't otherwise been installed in one of the standard places yet.

The LD_LIBRARY_PATH environment variable contains a colon-separated list of directories, just like PATH does.

Hope this helps

-- 
Lew Pitcher


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Karl-Heinz Herrmann [kh1 at khherrmann.de]
Fri, 15 Sep 2006 23:35:16 +0200

On Sat, 16 Sep 2006 02:10:33 +0530 "Himanshu Thappa" <himanshut at KPITCummins.com> wrote:

> Plz tell me what LD_Library_path does?tel me asap.

nothing.

LD_LIBRARY_PATH on the other hand is telling the linker [LD] which path [PATH] it should look for libraries [LIBRARY]. Terribly difficult to guess....

K.-H.


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Rick Moen [rick at linuxmafia.com]
Fri, 15 Sep 2006 14:41:19 -0700

Quoting Himanshu Thappa (himanshut at KPITCummins.com):

> Hi James 
> Plz tell me what LD_Library_path does?tel me asap.

Himanshu --

As a Frequently Asked Question, this is covered in my knowledgebase, so I definitely can answer it even though my name isn't "James".

(See: "LD_LIBRARY_PATH" on http://linuxmafia.com/kb/Admin for full details.)

LD_LIBRARY_PATH is a shell environment variable that allows you to specify where dynamic libraries can be found, in preference to any runtime or default system linker path.

LD_LIBRARY_PATH is a bad kludge, because the risk of security problems or unintended side effects (e.g., on other programs) is much too large. A much better solution is to either run the program in question using a wrapper script that defines the desired LD_LIBRARY_PATH environment just for that one program, or -- better -- just recompile it using LDFLAGS defined appropriately in your configure script, rather than trying to fix library paths at runtime.

If using a wrapper script, be aware that called programs will inherit the parent process's environment, and thus the LD_LIBRARY_PATH setting.


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Rick Moen [rick at linuxmafia.com]
Tue, 26 Sep 2006 10:24:52 -0700

----- Forwarded message from Himanshu Thappa <himanshut at KPITCummins.com> -----

Date: Tue, 26 Sep 2006 21:27:56 +0530
From: Himanshu Thappa <himanshut@KPITCummins.com>
To: TAG <tag@lists.linuxgazette.net>
To: Rick Moen <rick at linuxmafia.com>
Subject: RE: [TAG] LD_Library_Path
hi..buddy.. culd u tel me in ur words wat exactly is the role of "AWK" in unix...and wat is the name of filesystem which supports linux/unix...?hopinf for ur reply..... Regards Himanshu Thappa 09881407689

______________________________

I have taken the liberty of excising the text here, which was Rick's original answer to Himanshu Thappa. --Kat

----- End forwarded message -----


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Thomas Adam [thomas.adam22 at gmail.com]
Tue, 26 Sep 2006 22:38:17 +0100

[ Please retain a Cc to tag at lists.linuxgazette.net in your replies. ]

On Wed, 27 Sep 2006 03:00:44 +0530 "Himanshu Thappa" <himanshut at KPITCummins.com> wrote:

> Hi Thomas..
> culd u tel me where r u located rite now.and thanks for this
> informtion.. 

I'm sat at my desk.

-- Thomas Adam

-- 
"If I were a witch's hat, sitting on her head like a paraffin stove, I'd
fly away and be a bat." -- Incredible String Band.


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Thomas Adam [thomas.adam22 at gmail.com]
Wed, 27 Sep 2006 17:13:07 +0100

On Wed, 27 Sep 2006 20:32:51 +0530 "Himanshu Thappa" <himanshut at KPITCummins.com> wrote:

> hey buddy..
> in wich country u r?and r u wrking in some compmnay or providing free
> suport to the ppl like me..? 

I am in England. I have just finished University and am now working for a small company that produces a firewall running on Linux. Note that I provide support free of charge just like I always have done.

You can read my bio on the linuxgazette of course:

http://linuxgazette.net/authors/adam.html

Only slightly out of date by about two weeks.

Can you please ensure you Cc tag at lists.linuxgazette.net in the future.

-- Thomas Adam


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Himanshu Thappa [himanshut at KPITCummins.com]
Thu, 28 Sep 2006 20:35:28 +0530

Hi Thomaas

I m sory i never made cc to the other..adres..but this time im making Cc as well.So at wat time u cme 2 office...and where in england?Im in india..and i thnk u r realy very supporting person.I havnt got time to go thru ur bio data but i'll soon go thru it.Keep in touch

Bye

Regards
Himanshu Thappa
(P) 09881407689
(O) 02039825000
Ext:-5648

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Thomas Adam [thomas.adam22 at gmail.com]
Thu, 28 Sep 2006 16:44:29 +0100

On Thu, 28 Sep 2006 20:35:28 +0530 "Himanshu Thappa" <himanshut at KPITCummins.com> wrote:

> Hi Thomaas 
> I m sory i never made cc to the other..adres..but this time im making
> Cc as well.So at wat time u cme 2 office...and where in england?Im in
> india..and i thnk u r realy very supporting person.I havnt got time
> to go thru ur bio data but i'll soon go thru it.Keep in touch Bye

Thank you. I've been here at the Linuxgazette for about five years -- before that, I used to answer various questions on a personal basis.

As for my working hours, they're 9:00-5:30 (currently BST).

-- Thomas Adam


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Lew Pitcher [lpitcher at sympatico.ca]
Tue, 26 Sep 2006 18:53:40 -0400

On Tuesday 26 September 2006 13:24, Rick Moen wrote:

> ----- Forwarded message from Himanshu Thappa <himanshut at KPITCummins.com> 
-----

> 
> Date: Tue, 26 Sep 2006 21:27:56 +0530
> From: Himanshu Thappa <himanshut at KPITCummins.com>
> To: Rick Moen <rick at linuxmafia.com>
> Subject: RE: [TAG] LD_Library_Path
> 
> hi..buddy..

Hi, Himanshu. Call me "Lew". I don't go by the name "Buddy" :-)

> culd u tel me in ur words wat exactly is the role of "AWK" in unix

AWK is the initials of three of the early developers in the Unix environment. The A stands for Aho (A. V.), the W for Weinberger (P.J), and the K for Kernighan (B. W). At one point, these three developers cooperated and built a pattern scanning and processing language that they named AWK (after themselves). This language (developed sometime before Sept. 1978) became a standard tool for parsing and processing plain-text data. While mostly supplanted by more capable (and much more complex) text processing languages like Perl and Python, AWK remains one of the basic tools for text parsing available in Unix.

> ...and wat is the name of filesystem which supports linux/unix...?

/Which/ filesystem are you interested in? For Unix, there is/were several filesystems, including the original Unix filesystem and the Berkeley Fast Filesystem. There are others, mostly propriatary, that I can't name.

On the Linux side, there are ext (obsolete), ext2 and ext3. There's jfs, afs, reiserfs, xfs, minix, adfs, affs, coda, coherent, cramfs, efs, hfs, hpfs, iso9660, msdos, ncpfs, nfs, ntfs, qnx4, ramfs, romfs, smbfs, sysv, tmpfs, udf, ufs, umsdos, vfat, xenix, xiafs, along with some pseudo-filesystems like proc, tmpfs and usbfs. Which one are you interested in?

> hopinf  for ur reply.....  

I can tell that english is not your first language. I hope that I understood and answered your questions to your satisfaction.

-- 
Lew Pitcher


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Benjamin A. Okopnik [ben at linuxgazette.net]
Tue, 26 Sep 2006 23:02:26 -0400

On Tue, Sep 26, 2006 at 06:53:40PM -0400, Lew Pitcher wrote:

> 
> While mostly 
> supplanted by more capable (and much more complex) text processing languages 
> like Perl and Python, AWK remains one of the basic tools for text parsing 
> available in Unix.

For a while, Debian cheated and used Perl's "a2p" ("AWK to Perl" translator) instead of the real thing. Worse yet, they replaced that wonderful, "complete programming manual for AWK" man page with a tiny stub that essentially said "Read the Perl docs." As much as I like Perl, I was Quite Peeved: AWK was a useful utility, that man page was really well-written, and I just hated to see it go - I felt that new users would be losing something important, since I consider AWK a good stepping stone for those who want to learn the basics of programming. However, a little current research says:

ben at Fenrir:~$ readlink -f `which awk`
/usr/bin/mawk
- and the manpage looks like it's back to normal. Better yet, "apt-cache search awk$" tells me that GAWK is available as well (in fact, I just went ahead and installed it while typing this), so all is well in that part of the world.

* Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *


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Thomas Adam [thomas.adam22 at gmail.com]
Tue, 26 Sep 2006 23:02:26 -0400

On Tue, 26 Sep 2006 10:24:52 -0700 Rick Moen <rick at linuxmafia.com> wrote:

> ----- Forwarded message from Himanshu Thappa
> <himanshut at KPITCummins.com> -----
> hi..buddy..
> culd u tel me in ur words wat exactly is the role of "AWK" in
> unix...and wat is the name of filesystem which supports
> linux/unix...?hopinf  for ur reply..... Regards

I assume you realise that the two questions you've asked aren't related? Awk, is simply a general purpose programming language. Nothing more. It doesn't have a "role" in that it has some default use or predefined purpose. It's very useful for text-based processing -- especially columnar data.

As to your second question, the usual filesystem you'll find on linux-based systems is ext2/3 (ext3 is simply ext2 plus a journal). Other variants of filesystem include: ReiserFS, MinuxFS, Ext, JFS, XFS, etc.

If you provide us with more information, we might be abe to help you further.

-- Thomas Adam

-- 
"If I were a witch's hat, sitting on her head like a paraffin stove, I'd
fly away and be a bat." -- Incredible String Band.


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