linux atheros AR9285 wireless driver

현재 노트북의 불안정한 리눅스 와이어레스 드라이버를 안정적인 최신 드라이버로 교체.

유니코드 압축해제 in Linux

1. 압축 파일용 패키지 설치

어느 분이 멋진 펄 스크립트를 하나 올려주셨다. 이 스크립트를 설치하기 위해서는 추가적인 패키지를 하나 설치해야 한다.

$sudo apt-get install libarchive-zip-perl

이름을 보아하니, 펄에서 zip 파일을 다룰 수 있도록 하는 것인 듯 하다.

2. 스크립트 작성

이제, 준비가 끝났으니 스크립트를 작성해 보자.

$sudo vi /usr/local/bin/kozip

vi 편집기에서 아래와 같이 입력한다. 입력하기 전에 먼저 a 키나 i 키를 눌러 입력한 문자를 삽입하는 모드로 변경한 다음 입력해야 한다.

#!/usr/bin/perl
use strict;
use Encode;
use Archive::Zip;
my $zip = Archive::Zip->new();
$zip->read($ARGV[0]) == 0 or
die "$0: couldn't read $ARGV[0]\n";
foreach my $mref ($zip->members) {
my $n = decode("cp949",$mref->fileName);
print "Extracting $n\n";
$zip->extractMember($mref,$n) == 0 or
die "$0: couldn't extract $n\n";
}

입력이 모두 끝났으면 esc 키를 누르고 ZZ(shift누른 상태에서 z키 두 번)눌러서 저장한다.\

3. 실행준비

이제 kozip 이라는 스크립트를 실행하기 위해 준비해보자.

$sudo chmod 755 /usr/local/bin/kozip

준비 끝. 한글이름 파일이 깨져나오는 압축 파일은 kozip [압축파일] 이라고 입력하면 압축을 제대로 풀 수 있다.



일본어의 압축해제.

#!/usr/bin/perl
use strict;
use Encode;
use Archive::Zip;
my $zip = Archive::Zip->new();
$zip->read($ARGV[0]) == 0 or
die "$0: couldn't read $ARGV[0]\n";
foreach my $mref ($zip->members) {
my $n = decode("shiftjis",$mref->fileName);
print "Extracting $n\n";
$zip->extractMember($mref,$n) == 0 or
die "$0: couldn't extract $n\n";
}

Creating a shared and static library with the gnu compiler [gcc]

Creating a shared and static library with the gnu compiler [gcc]

Here's a summary on how to create a shared and a static library with gcc. The goal is to show the basic steps. I do not want to go into the hairy details. It should be possible to use this page as a reference.
These examples were tested and run on cygwin/Windows.
The code for the library
This is the code that goes into the library. It exhibits one single function that takes two doubles and calculates their mean value and returns it.
calc_mean.c

//#include

double mean(double a, double b) {
return (a+b) / 2;
}

The header file
Of course, we need a header file.
calc_mean.h

double mean(double, double);

Creating the static library
A static library is basically a set of object files that were copied into a single file. This single file is the static library. The static file is created with the archiver (ar).
First, calc_mean.c is turned into an object file:

gcc -c calc_mean.c -o calc_mean.o

Then, the archiver (ar) is invoked to produce a static library (named libmean.a) out of the object file calc_mean.o.

ar rcs libmean.a calc_mean.o

Note: the library must start with the three letters lib and have the suffix .a.
Creating the shared library
As with static libraries, an object file is created. The -fPIC option tells gcc to create position independant code which is necessary for shared libraries. Note also, that the object file created for the static library will be overwritten. That's not bad, however, because we have a static library that already contains the needed object file.

gcc -c -fPIC calc_mean.c -o calc_mean.o

For some reason, gcc says:

cc1: warning: -fPIC ignored for target (all code is position independent)

It looks like -fPIC is not necessary on x86, but all manuals say, it's needed, so I use it too.
Now, the shared library is created

gcc -shared -Wl,-soname,libmean.so.1 -o libmean.so.1.0.1 calc_mean.o

Note: the library must start with the three letter lib.
The programm using the library
This is the program that uses the calc_mean library. Once, we will link it against the static library and once against the shared library.
main.c

#include
#include "calc_mean.h"

int main(int argc, char* argv[]) {

double v1, v2, m;
v1 = 5.2;
v2 = 7.9;

m = mean(v1, v2);

printf("The mean of %3.2f and %3.2f is %3.2f\n", v1, v2, m);

return 0;
}

Linking against static library

gcc -static main.c -L. -lmean -o statically_linked

Note: the first three letters (the lib) must not be specified, as well as the suffix (.a)
Linking against shared library

gcc main.c -o dynamically_linked -L. -lmean

Note: the first three letters (the lib) must not be specified, as well as the suffix (.so)
Executing the dynamically linked programm

LD_LIBRARY_PATH=.
./dynamically_linked

Thanks
Thanks to Donn Morrison who helped me improve this page.

How to use openssl

Encryption
ex) openssl enc -des3 -salt -k 1234 -in filename -out filename.des3

Decryption
ex) openssl des3 -d -in filename -out filename

Encrypting and decrypting files from command line with gpg

Your Key

Private and public keys are at the heart of gpg’s encryption and decryption processes. The best first step is to create a key pair for yourself.

1. Generate a private key.

   gpg --gen-key
   

   You’ll have to answer a bunch of questions:

   1. What kind and size of key you want; the defaults are probably good enough.

   2. How long the key should be valid. You can safely choose a non-expiring key for your own use. If you plan to use a key for public signing, you might want to consider a yearly expiration.

   3. Your real name and e-mail address; these are necessary for identifying your key in a larger set of keys.

   4. A comment for your key, perhaps to distinquish a key used for special tasks like signing software releases. The comment can be empty.

   5. A passphrase. Whatever you do, don’t forget it! Your key, and all your encrypted files, will be useless if you do.

2. Generate an ASCII public version of your private key.

   gpg --armor --output pubkey.txt --export 'Your Name'
   

   You can freely distribute this file by sending it to friends, posting it on your web site, or whatever.

3. You might also want to register your key with public keyservers so that others can retrieve your key without having to contact you directly.

   gpg --send-keys 'Your Name' --keyserver hkp://subkeys.pgp.net
   

Encrypting a file for personal use

Encrypting files for your personal use is quite easy.

1. Encrypt a file called foo.txt. The argument to the --recipient option should be the all or part of the name you used when generating your private key.

   # the long version
   gpg --encrypt --recipient 'Your Name' foo.txt
   
   # using terse options
   gpg -e -r Name foo.txt
   

   The encrypted version of the file will by default be named foo.txt.gpg. You can modify that behavior using the --output (-o) option.

2. Decrypt the encrypted file. You’ll be asked to provide the passphrase you used when generating your private key. If you don’t use the --output option, the contents of the encrypted file will be sent to standard output.

   gpg --output foo.txt --decrypt foo.txt.gpg
   

If foo.txt is a file that you think you’ll want to edit and/or view on a regular basis, you might consider using make to reduce the amount of typing you’ll have to do. Here’s an example Makefile (to use it, you’ll need to make sure that the leading whitespace in the targets is composed of Tabs, not ordinary spaces).

# example Makefile for viewing/editing an encrypted file
GPGID = you@your.address
FILEPLAIN = foo.txt
FILECRYPT = $(FILEPLAIN).gpg

GPG = gpg
RM = /bin/rm -i
VI = vim

all:
       @echo ""
       @echo "usage:"
       @echo ""
       @echo "* make view -- to see $(FILEPLAIN)"
       @echo "* make edit -- to edit $(FILEPLAIN)"
       @echo ""

edit:
       @umask 0077;\
         $(GPG) --output $(FILEPLAIN) --decrypt $(FILECRYPT)
       @$(VI) $(FILEPLAIN)
       @umask 0077;\
         $(GPG) --encrypt --recipient $(GPGID) $(FILEPLAIN)
       @$(RM) $(FILEPLAIN)

view:
       @umask 0077; $(GPG) --decrypt $(FILECRYPT) | less

Encrypting a file for someone else

The really cool thing about GnuPG is that you can safely encrypt files for others using publicly available keys.

1. Import your friend’s key, which you might have received via e-mail or on a floppy. If the file is named key.asc, then just use the --import option to add it to your keyring:

   gpg --import key.asc
   

   That’s it! You can verify the import using the --list-keys option.

2. Alternatively, you might be able to find your friend’s key on a public keyserver.

   gpg --search-keys 'myfriend@his.isp.com' \
    --keyserver hkp://subkeys.pgp.net
   

   Here’s what a session looks like when someone searches for my key.

   $ gpg --search-keys heinlein@madboa
   gpgkeys: WARNING: this is an *experimental* HKP interface!
   gpgkeys: searching for "heinlein@madboa" from HKP server
   subkeys.pgp.net
   Keys 1-5 of 5 for "heinlein@madboa"
   (1)     Paul Heinlein 
            1024 bit DSA key 8F54CA35, created 2000-11-10
   (2)     Paul Heinlein 
            1024 bit DSA key 8F54CA35, created 2000-11-10
   (3)     Paul Heinlein 
            1024 bit DSA key 8F54CA35, created 2000-11-10
   (4)     Paul Heinlein 
            1024 bit DSA key 8F54CA35, created 2000-11-10
   (5)     [user attribute packet]
            1024 bit DSA key 8F54CA35, created 2000-11-10
   Enter number(s), N)ext, or Q)uit > 1
   gpgkeys: WARNING: this is an *experimental* HKP interface!
   gpg: key 8F54CA35: public key "Paul Heinlein "
   imported
   gpg: Total number processed: 1
   gpg:               imported: 1
   

   You’ll note that my key has four different e-mail addresses attached to it. That’s perfectly normal.

3. Once you’ve got the other person’s public key, encrypt a file using it.

   gpg --encrypt --recipient 'myfriend@his.isp.net' foo.txt
   

   You’ll end up with a file called foo.txt.gpg that you can send as an e-mail attachment or make available for downloading via ftp or the web.

Decrypting a file from someone else

If someone sends you an encrypted file, the file has typically been encrypted using your public key. Decrypting it is no different than decrypting a file you’ve encrypted for your own use.

gpg --output foo.txt --decrypt foo.txt.gpg

Basic Key Management

After a while, you will probably have several keys in your ring. It’s easy to list them all:

gpg --list-keys

Should you lose trust in or contact with a person with a key in your ring, you’ll want to delete it:

gpg --delete-key 'myfriend@his.isp.com'

Mount Example

# /etc/fstab: static file system information.
#
# Use 'vol_id --uuid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
#
proc /proc proc defaults 0 0
# / was on /dev/sda1 during installation
UUID=a3ea494a-508e-46ef-b7ed-229ea5a2b6ee / ext3 relatime,errors=remount-ro 0 1
# /home was on /dev/sdb1 during installation
UUID=cc4e6b59-bd61-4b33-b2d6-b5504cad0afa /home ext3 relatime 0 2
# swap was on /dev/sda5 during installation
UUID=fe5164e0-dea3-4b5d-aeb4-0aa8a7b03a59 none swap sw 0 0
/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0
# This is 750G partition of one terabyte hitachi hard drive.
UUID=21E53765421D089F /home/userid/Archives ntfs-3g exec,rw,dev,suid,async,utf8,uid=1000,gid=1000,umask=022 0 0



*How to Check UUID.

ls -l /dev/disk/by-uuid/

Or

blkid /dev/sda3 //number is depends on hard disk.



Use mount command in a terminal

mount /dev/sda3 /home/gray/Archives -t ntfs-3g -o exec,rw,dev,suid,async,utf8,uid=1000,gid=1000,umask=022

CD ISO Image In Linux

Create Image from CDROM
dd if=/dev/cdrw of=/home/user/temp/image.iso




Mount ISO image to Computer
mount -o loop -t iso9660 /home/gray/image.iso /mnt/cdrom