구차니의 잡동사니 모음

$ ls --full-time 

# systemctl stop firewalld 

# firewall-cmd --list-all 

# firewall-cmd --add-port=21/tcp

# firewall-cmd --remove-port=21/tcp

# .

-bash: .: filename argument required

.: usage: . filename [arguments] 

BASH BUILTIN COMMANDS

       Unless  otherwise  noted, each builtin command documented in this section as

       accepting options preceded by -  accepts  --  to  signify  the  end  of  the

       options.  The :, true, false, and test builtins do not accept options and do

       not treat -- specially.  The exit, logout, break, continue, let,  and  shift

       builtins accept and process arguments beginning with - without requiring --.

       Other builtins that accept arguments but  are  not  specified  as  accepting

       options  interpret arguments beginning with - as invalid options and require

       -- to prevent this interpretation.

       : [arguments]

              No effect; the command does nothing beyond  expanding  arguments  and

              performing any specified redirections.  A zero exit code is returned.

        .  filename [arguments]

       source filename [arguments]

              Read and execute commands from filename in the current shell environ‐

              ment and return the exit status of the  last  command  executed  from

              filename.   If  filename does not contain a slash, file names in PATH

              are used  to  find  the  directory  containing  filename.   The  file

              searched  for  in  PATH  need not be executable.  When bash is not in

              posix mode, the current directory is searched if no file is found  in

              PATH.   If  the  sourcepath  option  to  the shopt builtin command is

              turned off, the PATH is not searched.  If any arguments are supplied,

              they  become  the  positional  parameters  when filename is executed.

              Otherwise the positional parameters are unchanged.  The return status

              is  the  status of the last command exited within the script (0 if no

              commands are executed), and false if filename is not found or  cannot

              be read. 

# . ls

-bash: .: /usr/bin/ls: cannot execute binary file 

admin-openrc.sh 파일을 로드하여 Identity 서비스에 대한 위치와 admin 프로젝트 및 사용자 credential과 함께 환경 변수를 넣어줍니다:

$ source admin-openrc.sh 

The check-update command will refresh the package index and check for available updates:

yum check-update 

yum update package_name

지정된 패키지를 사용 가능한 최신 버전으로 업데이트하는데 사용됩니다. 지정된 패키지가 없을 경우, yum은 설치된 모든 패키지를 업데이트하게 됩니다.

--obsoletes 옵션을 사용할 경우 (예: yum --obsoletes package_name), yum은 오래된 패키지를 처리하게 됩니다. 따라서, 오래된 패키지는 업데이트를 하는 동안 적절히 삭제 및 교체됩니다.

yum check-update

이 명령으로 업데이트가 설치된 패키지에 적용할 수 있는지에 대한 여부를 확인할 수 있습니다. 업데이트를 적용할 수 있을 경우 yum은 전체 리포지터리에서 모든 패키지 목록을 반환합니다. 

Names incorporating Firmware/BIOS provided index numbers for on-board devices (example: eno1)

Names incorporating Firmware/BIOS provided PCI Express hotplug slot index numbers (example: ens1)

Names incorporating physical/geographical location of the connector of the hardware (example: enp2s0)

Names incorporating the interfaces's MAC address (example: enx78e7d1ea46da)

Classic, unpredictable kernel-native ethX naming (example: eth0) 

Change the network device naming scheme from ethX to a physical location-based name for easy identification and use.

Systems, particularly servers, with multiple network ports, name the ports ethX in a non-deterministic order, and are therefore not useful for system administrators. 

ifconfig em1 down

ip link set em1 name eth0

ifconfig eth0 up