The link above provides detailed explanation with screenshots. It also has some other simple methods that could be tried before doing this manually. Since it is not accessible from some regions let me describe the method that worked for me.

  1. Go to the OpenPGP Public Key Server. There you can enter your key into the Search String field, leaving everything else as is, then click "Search!".
    When searching for a key, always prepend 0x to it! This means that, for example, you have to search for 0x6AF0E1940624A220 instead of 6AF0E1940624A220.
  2. Click on the link provided in the pub section. This should take you to page containing the key. The page's heading should be similar to Public Key Server -- Get "0x6AF0E1940624A220"
  3. Copy everything from underneath the title (starting from -----BEGIN PGP PUBLIC KEY BLOCK-----) and save it in a file (e.g. key1).
  4. Once you have the file, run the following command

    sudo apt-key add key1

You will get an "OK" response.

And you are done. Repeat the procedure of other keys that might be missing.



에러메시지에 보면 마지막 PUBLIC KEY 하고 뒤에 키값이 나온다....

OpenPGP Public Key Server 링크 클릭 후 그 키 값 앞에 0x 를 붙여서 검색..

그리고 나온 링크를 클릭하면 key 값이 나오는데 그걸 복사해서 저장한다.

그리고 sudo apt-key add 키파일명 을 해주고 apt-get update 를 다시 실행.

vim 에서
     vim에서는 dos mode의 화일을 읽어도 화면에 ^M을 표시하지 않습니다.
     대신 밑에 [dos] 라고 나타납니다.
     다음과 같이 해서 unix mode로.. 즉 ^M을 빼는것입니다.

     :set fileformat=unix

     반대로 unix mode에서 dos mode로 바꾸고 싶다면

     :set fileformat=dos

CentOS 7 에서 로케일 변경하는 방법입니다.

현재 사용가능한 한글관련 로케일

# localectl list-locales | grep -i ko

utf8 로 변경

 # localectl set-locale LANG=ko_KR.utf8

수동으로 변경시는 /etc/locale.conf 파일을 만들어 아래 내용 추가


서버 부팅 후 로케일 설정 확인

# locale

# cat /etc/locale.conf
[2] Install MRTG, SNMP.
[root@dlp ~]#
yum -y install net-snmp net-snmp-utils mrtg
[3] Configure SNMP (Simple Network Management Protocol).
[root@dlp ~]#
vi /etc/snmp/snmpd.conf
# line 41: comment out

com2sec notConfigUser   default       public
# line 74,75: uncomment and change

# change to your local network for "mynetwork" section

# change comunity name except public or private

com2sec local

com2sec mynetwork
# line 78,79: uncomment and change

group MyRWGroup

group MyROGroup
# line 85: uncomment

view all    included  .1                               80

# line 93,94: uncomment and change

access MyROGroup ""
  all   none   none

access MyRWGroup ""
  all   all      all
[root@dlp ~]#
systemctl start snmpd

[root@dlp ~]#
systemctl enable snmpd
# show status (replace the "Serverworld" to your comunity name)

[root@dlp ~]#
snmpwalk -v2c -c Serverworld localhost system

SNMPv2-MIB::sysDescr.0 = STRING: Linux 3.10.0-229.4.2.el7.x86_64 #1 SMP Wed May.....
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (91954) 0:15:19.54
SNMPv2-MIB::sysContact.0 = STRING: Root <root@localhost> (configure /etc/snmp
SNMPv2-MIB::sysORUpTime.9 = Timeticks: (4) 0:00:00.04
SNMPv2-MIB::sysORUpTime.10 = Timeticks: (4) 0:00:00.04
[4] Configure MRTG.
[root@dlp ~]#
cfgmaker --snmp-options=:::::2 --ifref=descr --ifdesc=descr Serverworld@ > /etc/mrtg/mrtg.cfg

[root@dlp ~]#
vi /etc/mrtg/mrtg.cfg
# line 8: add

WorkDir: /var/www/mrtg
# line 16: uncomment

Options[_]: growright, bits
# near line 75: uncomment all from the line & change MaxBytes value

Target[]: \eth0:Serverworld@
noHC[]: yes
SetEnv[]: MRTG_INT_IP="" MRTG_INT_DESCR="eth0"

Title[]: eth0 --
PageTop[]: <h1>eth0 --</h1>
# execute mrtg 3 times (display warnings until 3 times)

[root@dlp ~]#
for (( i=1 ; i <= 3 ; i++ )); do env LANG=C mrtg /etc/mrtg/mrtg.cfg; done

2015-06-16 19:54:12, Rateup WARNING: /usr/bin/rateup could not read the primary log file for 2015-06-16 19:54:12, Rateup WARNING: /usr/bin/rateup The backup log file for was invalid as well 2015-06-16 19:54:12, Rateup WARNING: /usr/bin/rateup Can't rename to updating log file
# generate index file

[root@dlp ~]#
indexmaker --columns=1 /etc/mrtg/mrtg.cfg > /var/www/mrtg/index.html
# add in Cron

[root@dlp ~]#
vi /etc/cron.d/mrtg
*/5 * * * * root LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg --lock-file /var/lock/mrtg/mrtg_l --confcache-file /var/lib/mrtg/mrtg.ok
[5] Configure httpd to access MRTG site from other hosts.
[root@dlp ~]#
vi /etc/httpd/conf.d/mrtg.conf
# line 10: uncomment and add access permission, line 11: add DirectoryIndex

Require ip
DirectoryIndex index.html
[root@dlp ~]#
systemctl start httpd

[6] Access to the "http://(MRTG hostname or IP address)/mrtg/" from a client with HTTP, then it's possible to see MRTG site.


출처 :

There is an update to this post available: UUIDs and Linux: Everything you ever need to know.

The Universally Unique Identifier can be used to identify a device independent form its mount point or device name. This is more and more important as many devices today support hot-plugging or are external anyway. Therefore it makes sometimes sense to access a device (for example in fstab) not by device name but by the UUID.

There are several ways to get the UUID. The first one uses the /dev/ directory. While you are on is you might want to check other by-* directories, I never knew of them.

$ ls -l /dev/disk/by-uuid
lrwxrwxrwx 1 root root 10 11. Okt 18:02 53cdad3b-4b01-4a6c-a099-be1cdf1acf6d -> ../../sda2

Another way to get the uuid by usage of the tool blkid:

$ blkid /dev/sda1
/dev/sda1: LABEL="/" UUID="ee7cf0a0-1922-401b-a1ae-6ec9261484c0" SEC_TYPE="ext2" TYPE="ext3"

There you also get the label and other information. Quite usefule.

Btw., if you wonder how “unique” this unique is, here a quote from Wikipedia:

1 trillion UUIDs would have to be created every nanosecond for 10 billion years to exhaust the number of UUIDs.

Pretty unique.

Thanks to Linux By Examples for the initial howto.


  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 6
  • 64 bit architecture
  • 32 bit packages installed sharing some files with the 64 bit ones


  • Files are conflicting between 64 and 32 bit packages, how to fix it ?
  • yum update or yum install fails with package conflict between 64 bit and 32 bit package architectures.
  • 32 bit package showing conflict problem with 64 bit package.
Transaction Check Error:
file /usr/share/man/man1/ca.1ssl.gz from install of openssl-0.9.8e-27.el5_10.3.x86_64 conflicts with file from package openssl-0.9.8e-27.el5_10.1.i686
file /usr/share/man/man1/req.1ssl.gz from install of openssl-0.9.8e-27.el5_10.3.x86_64 conflicts with file from package openssl-0.9.8e-27.el5_10.1.i686
file /usr/share/man/man1/x509.1ssl.gz from install of openssl-0.9.8e-27.el5_10.3.x86_64 conflicts with file from package openssl-0.9.8e-27.el5_10.1.i686


You can configure the yum client to update only a package of the exact architecture installed on the system.

Perform the following steps to remove duplicate packages(i.e. 32-bit and 64-bit packages installed on server which is causing the dependency issues).

  1. Install the yum-utils package:

    # yum install yum-utils
  2. The package-cleanup --dupes lists all duplicate packages:

    # package-cleanup --dupes        
  3. The package-cleanup --cleandupes removes the duplicates (it asks for a confirmation to remove all duplicates unless the -y switch is given):

    # package-cleanup --cleandupes   
  4. Edit /etc/yum.conf, set the following line:

  5. Run yum command:

    # yum clean all
    # yum update

CentOS(리눅스)를 운영중인 장비에 하드디스크 등 저장장치를 추가 하면


디스크를 이용하기 위해서 다음과 같은 작업을 해줘야 합니다.


디스크 설치 후

fdisk –l 을 이용해서 디스크 정보를 확인합니다.

새로 설치된 디스크는 파티션 정보가 없습니다.


디스크 정보를 확인 했으면 fdisk 를 실행 합니다.

fdisk <장치명> (예 : fdisk /dev/sdb)


fdisk 메뉴를 확인하고 싶으시면 m을 입력하시면 됩니다.


p를 입력해서 파티션 정보를 확인합니다.

파티션이 없는 것을 확인 할 수 있습니다.

n 을 입력하면 파티션을 새롭게 만들 수 있습니다.

n을 누르면 두개의 메뉴가 나옵니다.

e(extended) 확장 파티션과, p(primary partition) 주파티션을 선택 할 수 있습니다.

주로 사용하는 주 파티션을 선택하고 partition number 는 첫번째 파티션 이니까 1번을 선택했습니다.

파티션넘버 다음에는 파티션의 크기를 설정할 수 있습니다. 용량으로 나오지가 않고

Cylinder 크기로 나옵니다. 시작 점과 종료 점을 선택해 주면 됩니다.

디스크 전체를 하나의 파티션으로 설정하는 경우에는 엔터, 엔터 로 진행하셔도 됩니다.

파티션 사이즈까지 설정 완료 하였으면, w를 눌러 정보를 저장합니다.


파티션 설정이 끝났으면 원하는 파일 형식으로 파티션을 포맷합니다.

Ext4 형식의 경우에는 아래와 같습니다.

mkfs.ext4 <디스크명> <예 : mkfs.ext4 /dev/sdb1>


포멧이 완료 되면 해당 파티션을 마운트 합니다.


마운트 방법은

mount –t ext4 /dev/sdb1 /data

mount –t <파일시스템형식> <파티션명> <마운트할위치> 입니다


부팅시에 자동으로 마운트를 되게 하기 위해서는 /etc/fstab을 수정해 저야 합니다.

Centos 6.3부터는 fstab 마운트에 UUID를 이용하고 있습니다.

UUID를 확인하기 위해서는 blkid 명령어를 이용하거나

ls –l /dev/disk/by-uuid 를 통해서 확인 하실 수 있습니다.


UUID를 확인한 후에 fatab을 열어 마운트할 내용을 추가해 줍니다.

Vi /etc/fatab

UUID = 추가할 파티션의 UUID <마운트할위치> ext4 defaults 1 2




출처 :

While trying to run a yum update I received the below warning message:


Setting up Install Process
Resolving Dependencies
There are unfinished transactions remaining. You might consider running yum-complete-transaction first to finish them.
--> Running transaction check


To resolve this yum-complete-transaction is required to complete the unfinished transactions.


yum-complete-transaction is a program which finds incomplete or aborted yum transactions on a system and attempts to complete them. It looks at the transaction-all* and transaction-done* files which can normally be found in /var/lib/yum if a yum transaction aborted in the middle of execution.

If it finds more than one unfinished transaction it will attempt to complete the most recent one first. You can run it more than once to clean up all unfinished transactions.



Run the following to install yum-utils (which provides yum-complete-transaction), cleanup and finish the transactions.

yum install yum-utils
yum clean all
/usr/sbin/yum-complete-transaction --cleanup-only


Now yum commands can be run without the unfinished transactions warning.

yum update

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