- Data Structures
- Linked List
- Binary Trees
- Tries
- Stacks
- Queues
- Vectors/ ArrayLists
- Hash Tables
- Algorithms
- Breadth First Search
- Depth First Search
- Binary Search
- Merge Sort
- Quick Sort
- Tree Insert/ Find
- Concepts
- Bit Manipulation
- Singleton Design Pattern
- Factory Design Pattern
- Memory(Stack vs. Heap)
- Recursion
- Big-O Time
Apr 17, 2012
Basic knowledge for coding interview
Mar 29, 2012
Bash script : cacti add graph to tree
I had to add much graph to graph trees on cacti over 80 nodes.
So I made the following script. I hope this will help you.
Please edit awk pattern phrases like "/host pattern/" as your situation.
So I made the following script. I hope this will help you.
Please edit awk pattern phrases like "/host pattern/" as your situation.
#!/bin/bash # # CopyLeft 2012 Joongjin, Bae # # CACTI_CLI_DIR=/var/www/cacti/cli cd $CACTI_CLI_DIR HOST_ID_LIST=`php -q add_tree.php --list-hosts | awk '/host pattern/ { print $1}'` TREE_ID=`php -q add_tree.php --list-trees | awk '/graph tree name/ { print $1}'` PARENT_ID_LIST=`php -q add_tree.php --list-nodes --tree-id=$TREE_ID | awk '/^Header/ {print $0}' | awk '/graph tree header node pattern/ {print $2}'` TARGET_GRAPH_ID_LIST=() for host_id in $HOST_ID_LIST do TARGET_GRAPH_ID_LIST=("${TARGET_GRAPH_ID_LIST[@]}" "`php -q add_tree.php --list-graphs --host-id=$host_id | awk '/add target graph pattern/ { print $1 "\n"}'`") done idx=0 for parent_id in $PARENT_ID_LIST do for graph_id in ${TARGET_GRAPH_ID_LIST[$idx]} do php -q add_tree.php --type=node --node-type=graph --tree-id=$TREE_ID --parent-node=$parent_id --graph-id=$graph_id done idx=$((idx+1)) done echo Mission Completed!
Feb 3, 2012
how to change language in netbeans
First of all, Let me show you my environment.
Windows 7 Professional 64bit
NetBeans7.1 64bit
Java 1.6 64bit
Now, I just changed my job and need to prepare new development environment. So I downloaded and installed NetBeans 7.1 English ver. But you know what I'm in Japan. So smart IDE, NetBeans, shows Japanese menu for me. It's cool But I'm Korean and I prefer to use it in English. As you know Java supports all of languages int the world.(It may be not.) Anyway, I asked Google Sensei.
Fortunately, I got one shot. Read the following URL.
It tells me use locale option like following.
- "C:\Program Files\NetBeans 7.1\bin\netbeans.exe" --locale en:US
I just add this option to shortcut property. OK. It works. But I want another way. Because I want to write Blog. :) I asked G Sensei again in Japanese. Sensei shows me other ways. Here is my solution.
Add language option to netbeans.conf file. This file is located in ↓ if you installed it in default path
- C:\Program Files\NetBeans 7.1\etc
Open it just add user.language=en to netbeans_default_options item. I show you my configuration.
(I don't change locale, cause I live in Japan ^^)
YOU WANT Japanese page? Just click the following URL.
Jan 5, 2012
The New Year Resolutions
Yes, I know that New Year already started 5 days ago.
I already decided my resolutions last year.
But I want to make it public and detail.
I hope publishing to force me achieve my resolutions.
OK, here are my resolutions.
1. I will be a manager. That's it.
2. I want to study computer science, statics and business. Big Data Analyst(he/she understands business) will be in high demand in 5 years. And analysis is fun.
3. My Home is My Dream.
I already decided my resolutions last year.
But I want to make it public and detail.
I hope publishing to force me achieve my resolutions.
OK, here are my resolutions.
- Promotion to Manager.
- Study of Computer Science and Statics in College.
- Buying my home.
1. I will be a manager. That's it.
2. I want to study computer science, statics and business. Big Data Analyst(he/she understands business) will be in high demand in 5 years. And analysis is fun.
3. My Home is My Dream.
------
Written on Jan. 4th 2022.
1. I was promoted to an engineering manager in 2016. But I was promoted to a team lead in 2012.
2. I started to study Stastics from 2012. But I finished my course in 2018.
3. I bought a house in 2013.
Dec 17, 2011
Sony vgn-cr60b windows xp drivers
You can download drivers if you click links.
Mobile Intel 965 Express Chipset Family
Intel® Graphics Media Accelerator Driver for Windows* XP
HDAUDIO Soft Data Fax Modem with SmartCP
Realtek RTL8101E Family PCI-E Fast Ethernet NIC
Realtek High Definition Audio Driver
LAN-Express AS IEEE 802.11g PCI-E Adapter
Mobile Intel 965 Express Chipset Family
Intel® Graphics Media Accelerator Driver for Windows* XP
HDAUDIO Soft Data Fax Modem with SmartCP
Realtek RTL8101E Family PCI-E Fast Ethernet NIC
Realtek High Definition Audio Driver
LAN-Express AS IEEE 802.11g PCI-E Adapter
Dec 13, 2011
Eclipse: java.lang.UnsupportedClassVersionError: Bad version number in .class file
Thrown when the Java Virtual Machine attempts to read a class file and determines that the major and minor version numbers in the file are not supported. from Java 6 API
When I checked out project source, the project didn't have .project and .classpath files.
(I'm using Eclipse 3.7.)
So I added Project Facets Java as 1.6 and used JRE1.4 for JRE System Library.
My project is supposed to work on Java 1.4.
But I compiled it with Java 1.6 because Project Facets is Java 1.6.
I fixed Project Facets and Java Compiler version and have no problem.
When I checked out project source, the project didn't have .project and .classpath files.
(I'm using Eclipse 3.7.)
So I added Project Facets Java as 1.6 and used JRE1.4 for JRE System Library.
My project is supposed to work on Java 1.4.
But I compiled it with Java 1.6 because Project Facets is Java 1.6.
I fixed Project Facets and Java Compiler version and have no problem.
Nov 15, 2011
Sep 27, 2011
How to reboot Solaris
Just type the following commands.
bash-3.00$shutdown -y -i6 -g0
or
bash-3.00$reboot
Aug 29, 2011
org.apache.xerces.dom.DeferredDocumentImpl.getXmlStandalone()Z reason
org.apache.xerces.dom.DeferredDocumentImpl.getXmlStandalone()Z
Reason : It occurs when xercesImpl-X.X.X.jar doesn't exist in the class path.
Solution : Just replace xerces-X.X-X.jar to xercesImpl-X.X.X.jar.
You can download xercesImpl-X.X.X.jar the following URL.
http://mirrors.ibiblio.org/pub/mirrors/maven/mule/dependencies/maven2/xerces/xercesImpl/2.9.1/xercesImpl-2.9.1.jar
Reason : It occurs when xercesImpl-X.X.X.jar doesn't exist in the class path.
Solution : Just replace xerces-X.X-X.jar to xercesImpl-X.X.X.jar.
You can download xercesImpl-X.X.X.jar the following URL.
http://mirrors.ibiblio.org/pub/mirrors/maven/mule/dependencies/maven2/xerces/xercesImpl/2.9.1/xercesImpl-2.9.1.jar
Jul 8, 2011
IE9 frameset tag issue
I've got a problem with IE9.
My web page doesn't show on IE9 document mode.
Because I used frameset tag, I thought my web page failed to satisfy HTML5 standard.
But my another page doesn't have any problem, even using same frameset tag.
I started to find why it happened. There is not answer on the net.
Master Google couldn't help me.(Also Bing and Yahoo)
So I quit searching it on the net and started finding the reason my self with developer tool of IE.
1. miss of javascript code -> deleted every javascript code, but it was same.
2. a bug of Tomcat 5.5 -> changed to 6.0, but it was same.
3. jsp -> quit using jsp, but...
4. 5. 6. ... 100. 101. ...
Finally, I found the reason after 4 days.
The reason was CSS. After I deleted the following line, My web page started working well.
My web page doesn't show on IE9 document mode.
Because I used frameset tag, I thought my web page failed to satisfy HTML5 standard.
But my another page doesn't have any problem, even using same frameset tag.
I started to find why it happened. There is not answer on the net.
Master Google couldn't help me.(Also Bing and Yahoo)
So I quit searching it on the net and started finding the reason my self with developer tool of IE.
1. miss of javascript code -> deleted every javascript code, but it was same.
2. a bug of Tomcat 5.5 -> changed to 6.0, but it was same.
3. jsp -> quit using jsp, but...
4. 5. 6. ... 100. 101. ...
Finally, I found the reason after 4 days.
The reason was CSS. After I deleted the following line, My web page started working well.
<link href="/css/style.css" rel="stylesheet" type="text/css"/link>
May 31, 2011
May 12, 2011
How to get ORACLE_HOME by SQL
I had to get Oracle alert log file path by SQL on 9i, 10g.
Because I didn't want to force a user input it.
First I tried the following SQL sentence.
SQL> select * from sysman.mgmt$software_homes;
win2k3svrvminst OraHome92 ORACLE_HOME D:\oracle\ora92
win2k3svrvminst OraDb10g_home1 ORACLE_HOME F:\oracle\product\10.2.0\db_1
win2k3svrvminst Independent Products INDEPENDENT N/A
(copied on SQL Developer)
I didn't know which ORACLE_HOME is proper one.
I should keep searching and tried this.
SQL>select substr(file_spec, 1, instr(file_spec, '\', -1, 2) -1) ORACLE_HOME
from dba_libraries
where library_name = 'DBMS_SUMADV_LIB';
(On Unix, substitute with '/' )
This SQL showed me ORACLE_HOME, C:\oracle\product\10.2.0\db_1, but it required me as sysdba on 10g.
Because my application can't get sysdba's id and password, I had to keep searching.
SQL> set autopri on
SQL> var oracle_home varchar2(255)
SQL> exec dbms_system.get_env('ORACLE_HOME',:ORACLE_HOME)
It works too, but I don't want to use PL/SQL procedure.
Finally, I quited searching.
But this article can help some people who want to know "How to get ORACLE_HOME by using SQL".
Because I didn't want to force a user input it.
First I tried the following SQL sentence.
SQL> select * from sysman.mgmt$software_homes;
win2k3svrvminst OraHome92 ORACLE_HOME D:\oracle\ora92
win2k3svrvminst OraDb10g_home1 ORACLE_HOME F:\oracle\product\10.2.0\db_1
win2k3svrvminst Independent Products INDEPENDENT N/A
(copied on SQL Developer)
I didn't know which ORACLE_HOME is proper one.
I should keep searching and tried this.
SQL>select substr(file_spec, 1, instr(file_spec, '\', -1, 2) -1) ORACLE_HOME
from dba_libraries
where library_name = 'DBMS_SUMADV_LIB';
(On Unix, substitute with '/' )
This SQL showed me ORACLE_HOME, C:\oracle\product\10.2.0\db_1, but it required me as sysdba on 10g.
Because my application can't get sysdba's id and password, I had to keep searching.
SQL> set autopri on
SQL> var oracle_home varchar2(255)
SQL> exec dbms_system.get_env('ORACLE_HOME',:ORACLE_HOME)
It works too, but I don't want to use PL/SQL procedure.
Finally, I quited searching.
But this article can help some people who want to know "How to get ORACLE_HOME by using SQL".
May 10, 2011
How to know Oracle DB log files' path
ALERT LOG
Oracle writes the alert.log file to the directory as specified by BACKGROUND_DUMP_DEST parameter.
If it is not set, the alert.log will be created in the ORACLE_HOME/rdbms/trace directory.
SQL> show parameter BACKGROUND_DUMP_DEST
NAME TYPE
------------------------------------ ---------------------------------
VALUE
------------------------------
background_dump_dest string
/u01/app/oracle/diag/rdbms/trace
LISTNER LOG
Oracle writes listener.log file to ORACLE_HOME/NETWORK/log directory in usual.
You can confirm the path of listner.log file using "lsnrctl status" command.
[oracle@helium ~]$ lsnrctl
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 10-5月 -2011 14:55:15
Copyright (c) 1991, 2009, Oracle. All rights reserved.
LSNRCTLへようこそ。詳細は"help"と入力してください。
LSNRCTL> status
(DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))に接続中
リスナーのステータス
------------------------
別名 LISTENER
バージョン TNSLSNR for Linux: Version 11.2.0.1.0 - Production
開始日 13-4月 -2011 15:47:37
稼働時間 26 日 23 時間 7 分 41 秒
トレース・レベル off
セキュリティ ON: Local OS Authentication
SNMP OFF
パラメータ・ファイル /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
ログ・ファイル /u01/app/oracle/diag/tnslsnr/helium/listener/alert/log.xml
リスニング・エンドポイントのサマリー...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=helium.workslan)(PORT=1521)))
サービスのサマリー...
サービス"kiban.workslan"には、1件のインスタンスがあります。
インスタンス"kiban"、状態READYには、このサービスに対する1件のハンドラがあります...
サービス"kibanXDB.workslan"には、1件のインスタンスがあります。
インスタンス"kiban"、状態READYには、このサービスに対する1件のハンドラがあります...
コマンドは正常に終了しました。
Oracle writes the alert.log file to the directory as specified by BACKGROUND_DUMP_DEST parameter.
If it is not set, the alert.log will be created in the ORACLE_HOME/rdbms/trace directory.
SQL> show parameter BACKGROUND_DUMP_DEST
NAME TYPE
------------------------------------ ---------------------------------
VALUE
------------------------------
background_dump_dest string
/u01/app/oracle/diag/rdbms/trace
LISTNER LOG
Oracle writes listener.log file to ORACLE_HOME/NETWORK/log directory in usual.
You can confirm the path of listner.log file using "lsnrctl status" command.
[oracle@helium ~]$ lsnrctl
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 10-5月 -2011 14:55:15
Copyright (c) 1991, 2009, Oracle. All rights reserved.
LSNRCTLへようこそ。詳細は"help"と入力してください。
LSNRCTL> status
(DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))に接続中
リスナーのステータス
------------------------
別名 LISTENER
バージョン TNSLSNR for Linux: Version 11.2.0.1.0 - Production
開始日 13-4月 -2011 15:47:37
稼働時間 26 日 23 時間 7 分 41 秒
トレース・レベル off
セキュリティ ON: Local OS Authentication
SNMP OFF
パラメータ・ファイル /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
ログ・ファイル /u01/app/oracle/diag/tnslsnr/helium/listener/alert/log.xml
リスニング・エンドポイントのサマリー...
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=helium.workslan)(PORT=1521)))
サービスのサマリー...
サービス"kiban.workslan"には、1件のインスタンスがあります。
インスタンス"kiban"、状態READYには、このサービスに対する1件のハンドラがあります...
サービス"kibanXDB.workslan"には、1件のインスタンスがあります。
インスタンス"kiban"、状態READYには、このサービスに対する1件のハンドラがあります...
コマンドは正常に終了しました。
May 2, 2011
How to log(write) facility and priority to syslog on Linux(RedHat)
On RHEL 5 or higher version.(CentOS 5 or higher ver.), logging the syslog facility and priority is possible.
Add -S or -SS to SYSLOGD_OPTIONS in /etc/sysconfig/syslog and restart the syslog service for the change to take effect.
example)
$ cat /etc/sysconfig/syslog
# Options to syslogd
# -m 0 disables 'MARK' messages.
# -r enables logging from remote machines
# -x disables DNS lookups on messages recieved with -r
# See syslogd(8) for more details
SYSLOGD_OPTIONS="-m 0 -SS -r"
$ service syslog restart
Now you can confirm the facility and priority in your syslog.
$ cat /var/log messages
May 1 04:02:02 helium syslogd 1.4.1: restart.
May 2 13:09:55 helium kernel: Kernel logging (proc) stopped.
May 2 13:09:55 helium kernel: Kernel log daemon terminating.
May 2 13:09:57 helium exiting on signal 15 <-- before
May 2 13:09:57 helium syslogd 1.4.1: restart (remote reception). <-- after
May 2 13:09:57 helium kernel: klogd 1.4.1, log source = /proc/kmsg started.
Add -S or -SS to SYSLOGD_OPTIONS in /etc/sysconfig/syslog and restart the syslog service for the change to take effect.
example)
$ cat /etc/sysconfig/syslog
# Options to syslogd
# -m 0 disables 'MARK' messages.
# -r enables logging from remote machines
# -x disables DNS lookups on messages recieved with -r
# See syslogd(8) for more details
SYSLOGD_OPTIONS="-m 0 -SS -r"
$ service syslog restart
Now you can confirm the facility and priority in your syslog.
$ cat /var/log messages
May 1 04:02:02 helium syslogd 1.4.1: restart.
May 2 13:09:55 helium kernel: Kernel logging (proc) stopped.
May 2 13:09:55 helium kernel: Kernel log daemon terminating.
May 2 13:09:57 helium exiting on signal 15 <-- before
May 2 13:09:57
May 2 13:09:57
Apr 11, 2011
bash if grammar or(||) and(&&) (if文の or and条件)
I had to check parameters.
I searched if grammar, but I couldn't get a example of if condition || condition.
So I changed key word for search. It was "condition expressions"
I've got the answer. OR condition is -o and AND condition is -a.
Here is the sample code.
OR condition
if ["$1" == "" -o "$2" == ""] ; then
exit 1
fi
AND condition
I searched if grammar, but I couldn't get a example of if condition || condition.
So I changed key word for search. It was "condition expressions"
I've got the answer. OR condition is -o and AND condition is -a.
Here is the sample code.
OR condition
if ["$1" == "" -o "$2" == ""] ; then
exit 1
fi
AND condition
if ["$1" == "" -a "$2" == ""] ; then
exit 1
fi
Apr 8, 2011
Linux version check
Linuxのバージョンを確認する必要があって調べてみた。
#uname -a
Linux localhost.localdomain 2.6.18-194.el5 #1 SMP Fri Apr 2 14:58:35 EDT 2010 i686 i686 i386 GNU/Linux
#cat /proc/version
Linux version 2.6.18-194.el5 (mockbuild@builder16.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Fri Apr 2 14:58:35 EDT 2010
#cat /etc/redhat-release
CentOS release 5.5 (Final)
#uname -a
Linux localhost.localdomain 2.6.18-194.el5 #1 SMP Fri Apr 2 14:58:35 EDT 2010 i686 i686 i386 GNU/Linux
#cat /proc/version
Linux version 2.6.18-194.el5 (mockbuild@builder16.centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) #1 SMP Fri Apr 2 14:58:35 EDT 2010
#cat /etc/redhat-release
CentOS release 5.5 (Final)
Apr 7, 2011
Linux ユーザの全てのプロセスをkillするスクリプト
社内のLinuxサーバに無限にプロセスを生成するスクリプトが実行されたので
該当ユーザの全てのプロセスをkillするスクリプトを作ってみた。
#!bin/bash
uid=$1
pids=`ps ax -o uid,pid | grep $uid 2> /dev/null | awk '{print $2}'`
for pid in $pids
do
if [ $pid != $$ ]; then
echo "${user}: ${pid} killed"
kill -KILL $pid
fi
done
ちなみにそのユーザはbashのプロセスをずっと生成したので
以下のコマンドでも対応できる。
killall bash
rootユーザなら以下のコマンドで他のユーザの全てのプロセスをkillすることもできる。
該当ユーザの全てのプロセスをkillするスクリプトを作ってみた。
#!bin/bash
uid=$1
pids=`ps ax -o uid,pid | grep $uid 2> /dev/null | awk '{print $2}'`
for pid in $pids
do
if [ $pid != $$ ]; then
echo "${user}: ${pid} killed"
kill -KILL $pid
fi
done
ちなみにそのユーザはbashのプロセスをずっと生成したので
以下のコマンドでも対応できる。
killall bash
rootユーザなら以下のコマンドで他のユーザの全てのプロセスをkillすることもできる。
killall5
Solarisの vmstat見方メモ
以前AIXのvmstatの見方を説明したが、
今回はSolaris。
$ vmstat 1 3
kthr memory page disk faults cpu
r b w swap free re mf pi po fr de sr f0 s6 s1 s1 in sy cs us sy id
0 0 0 1013264 74720 4 5 29 3 3 0 0 -0 -0 0 0 434 85 70 2 3 95
0 3 0 1011328 96624 11 22 0 0 0 0 0 0 0 0 0 449 137 78 1 3 96
0 0 0 1011328 96624 7 7 0 0 0 0 0 0 0 0 0 407 88 66 0 3 97
主に仕事で必要な情報はメモリ。
AIXと違うのはまず単位がKBであること、
AIXはページ単位だったため4を掛け算する必要があった。
(ページは4KB)
そしてswap項目は使用可能なvirtual memoryサイズ、
AIXはすでに使われた仮想メモリ領域を意味する。
freeはAIXと同じく物理メモリの使用可能サイズを意味する。
今回はSolaris。
$ vmstat 1 3
kthr memory page disk faults cpu
r b w swap free re mf pi po fr de sr f0 s6 s1 s1 in sy cs us sy id
0 0 0 1013264 74720 4 5 29 3 3 0 0 -0 -0 0 0 434 85 70 2 3 95
0 3 0 1011328 96624 11 22 0 0 0 0 0 0 0 0 0 449 137 78 1 3 96
0 0 0 1011328 96624 7 7 0 0 0 0 0 0 0 0 0 407 88 66 0 3 97
主に仕事で必要な情報はメモリ。
AIXと違うのはまず単位がKBであること、
AIXはページ単位だったため4を掛け算する必要があった。
(ページは4KB)
そしてswap項目は使用可能なvirtual memoryサイズ、
AIXはすでに使われた仮想メモリ領域を意味する。
freeはAIXと同じく物理メモリの使用可能サイズを意味する。
Apr 5, 2011
line numbers in eclipse(行番号を表示する設定)
ソースレビューをしていたら自分のEclipseに行番号が表示されないことに気付き設定した。
忘れないためメモ
Windows(ウィンドウ) -> Preferences(設定) -> General(一般) – > Editors(エディター) -> Text Editors(テキスト・エディター)
“Show Line Numbers(行番号の表示)” チェックボックスにチェックを入れる
Subscribe to:
Posts (Atom)