Canon in D (Classical guitar) by Johann Pachelbel

How to unlock encrypted file system on Linux automatically

1. create a keyfile with random content

$ sudo su -
$ dd if=/dev/random of=/root/keyfile bs=1024 count=4

2. Add the file to LUKS

$ cryptsetyp luksAddKey /dev/sdb1 /root/keyfile

3. Edit /etc/crypttab

$ sdb1_crypt /dev/sdb1 /root/keyfile luks

4. Edit /etc/fstab

/dev/mapper/sdb1_crypt /media/Repository ext4 defaults 0 2

5. Reboot or Remount

Ternary operator(?:) in bash

Ternary operator is a short form of if/then/else

case $a in
    1) b=$c ;;
    *) b=$d ;;
esac

[[ $a=1 ]] && b=$c || b=$d
# At this case, 3rd part can be executed in case 2nd part fails

[[ $a=1 ]] && { b=$c; true; } || b=$d
# to avoid executing 3rd part by accident when 2nd part fails
## semicolon(;) is needed in {}

Count number of visitors(IP addresses) with IIS log files

* Instruction

1. Mount IIS log directory into Linux box

   $ sudo mount -t cifs -o ro,username=USER,password=PASSWD //HOST_IP/SHARE /MOUNT_POINT

2. Run

   #!/bin/bash
   
   site_num=(1 2 7 8)
   site_addr=("AAA.com" "BBB.com" "CCC.com" "DDD.com")
   echo "SITE_NAME DATE WEEK TRAFFIC DB_CONN VISITOR"
   for ix in ${!site_num[*]}
   do
     d=${site_num[$ix]}
     for f in $(ls W3SVC$d)
     do
       if [[ ${f:4:6} -ge $(date -d 'last monday' +"%y%m%d") && ${f:4:6} -lt $(date +"%y%m%d") ]]
       then
         visitors=$(cat W3SVC$d/$f | grep ^[0-9] | awk '{if(!match($9, /^192.168./) && !match($9, /^10.10./)) print $9}' | sort | uniq | wc -l)
         sendbytes=$(cat W3SVC$d/$f | grep ^[0-9] | awk '{print $16}' | awk '{total=total+$1}END{printf "%.f", total}')
         dbconns=$(cat W3SVC$d/$f | awk '{if(match($5,/^\/$/) || match($5,/asp/)) print $9}' | wc -l)
         weeknum=$(date -dyesterday +%V)
         [ $(date -d yesterday +%u) -eq 1 ] && {mon=$(date -d yesterday +%m.%d); true} || mon=$(date -d last-monday +%m.%d)
         [ $(date -d yesterday +%u) -eq 7 ] && {sun=$(date -d yesterday +%m.%d); true} || sun=$(date -d sunday +%m.%d)
         printf "%s 20%s-%s-%s %s(%s-%s) %s %s %s\n" ${site_addr[$ix]} ${f:4:2} ${f:6:2} ${f:8:2} $weeknum %mon %sun $sendbytes $dbconns $visitors
       fi
     done
   done
   

3. * Sample result

   SITE_NAME DATE WEEK TRAFFIC DB_CONN VISITOR
   AAA.com 2013-08-25 34(08.19-08.25) 12329500782 54908 7335
   BBB.com 2013-08-25 34(08.19-08.25) 13074318914 66700 6442
   CCC.com 2013-08-25 34(08.19-08.25) 23734108053 140609 12877
   DDD.com 2013-08-25 34(08.19-08.25) 8913154535 58417 5172
   

How to run NginX/PHP/MySQL on Mac

Needed to run DRUPAL on Mac

1. Install XCode
2. Install XCode Command Line Tools

XCode > Preferences > Downloads > Command Line Tools

3. Install Homebrew - Similar to MacPorts but better

$ ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go)"
$ brew doctor
$ brew tap josegonzalez/homebrew-php
$ brew tap homebrew/dupes

4. Install MySQL

$ brew install mysql
$ unset TMPDIR
$ mysql_install_db --verbose --user=`whoami` --basedir="$(brew --prefix mysql)" --datadir=/usr/local/var/mysql --tmpdir=/tmp
$ sudo mv /usr/local/opt/mysql/my-new.cnf /usr/local/opt/mysql/my.cnf
$ cp `brew --prefix mysql`/homebrew.mxcl.mysql.plist ~/Library/LaunchAgents/
$ launchctl load -w ~/Library/LaunchAgents/homebrew.mxcl.mysql.plist

5. Install NginX

$ brew install nginx
$ sudo cp `brew --prefix nginx`/homebrew.mxcl.nginx.plist /Library/LaunchDaemons/
$ sudo sed -i -e 's/`whoami`/root/g' `brew --prefix nginx`/homebrew.mxcl.nginx.plist
$ sudo mkdir /var/log/nginx/

6. Install PHP

$ brew install --without-apache --with-fpm --with-mysql php54
$ sudo cp `brew --prefix php54`/homebrew-php.josegonzalez.php54.plist  /Library/LaunchAgents/
$ sudo launchctl load -w /Library/LaunchAgents/homebrew-php.josegonzalez.php54.plist

How to extract MP3 audio from ASF in Linux environment

COMMAND :

for files in $(ls); do avconv -i $(files) -vn -acodec wmav2 -f asf ${files:0:2}".mp3"; done

If FILES are

01.asf

02.asf

03.asf

Manage multiple SSH private keys

There are 2 ways to manage multiple SSH private keys.

Step 0. Create a file named ~/.ssh/config

Step 1-1st, SSH can be configured with both host names and their identity files.

Host server1.remote.host
IdentityFile ~/.ssh/server1.remote.host.privatekey

Host server2.remote.host
IdentityFile ~/.ssh/server2.remote.host.privatekey

Step 1-2nd, SSH can be configured with a per-user configuration file.

$ vi config
Type the followings...

IdentityFie ~/.ssh/id_dsa_%h_%r

IdentityFie ~/.ssh/id_rsa_%h_%r

IdentityFie ~/.ssh/id_dsa

IdentityFie ~/.ssh/id_rsa

Save and quit.

$ssh username@remote.host

=> SSH client will try to read the private key at one of the following files

~/.ssh/id_dsa_remote.host_username

~/.ssh/id_rsa_remote.host_username

~/.ssh/id_dsa

~/.ssh/id_rsa

How to setup virtual directory with PHP support on Nginx

Setup virtual directory with PHP support.

location /phpmyadmin {
    alias /opt/phpmyadmin/;
    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass unix:/var/run/php5-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
    }
}

When to use mutliple virtual directories, seperate and include the configuration.
Create /etc/nginx/conf.d/php.inc

location ~ \.php$ {
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_index index.php;
    include fastcgi_params;
}

Include above file into the virtual directory configuration.

location /phpmyadmin {
    alias /opt/phpmyadmin/;
    include /etc/nginx/conf.d/php.inc;
}

LikeApache - htaccess on Nginx

Nginx does not use .htaccess file for the performance issue.

See details at LikeApache-htaccess