Homelab, Linux, JS & ABAP (~˘▾˘)~
 

Megarac SP Gui / IPMI

In meinem NAS nutze ich seit vielen Jahren als Motherboard ein ASRock C2550D4I mit einer recht stromsparsamen on-Board CPU und einer BMC/IPMI Schnittstelle, welche Fernwartung über einen separaten LAN Port möglich macht.

BMC = Baseboard Management Controllers
IPMI = Intelligence Platform Management Interface

Bei einem BMC Update hat sich leider die WebGui verabschiedet und ich musste mir die Sache auf der Konsole anschauen. Dafür habe ich IPMITOOL installiert und verwendet. Dabei stellte sich heraus, dass lediglich die Netzwerkeinstellungen verloren gegangen sind.

Hier einige hilfreiche Befehle im Umgang mit dem IPMITOOL, welche mir geholfen haben. Über diesen Weg lässt sich ebenfalls das Passwort des Admin Users zurücksetzen.

# install 
sudo apt install ipmitool

# display sensor & network settings
sudo ipmitool sensor
sudo ipmitool lan print 1

#set network settings
sudo ipmitool lan set 1 ipsrc static
sudo ipmitool lan set 1 ipaddr 192.168.178.3
sudo ipmitool lan set 1 defgw ipaddr 192.168.178.1


# Reset password
# https://support.oneidentity.com/de-de/kb/261220/reset-the-bmc-ipmi-password
sudo ipmitool user list 1
ID  Name	     Callin  Link Auth	IPMI Msg   Channel Priv Limit
1                    false   false      true       ADMINISTRATOR
2   admin            true    true       true       ADMINISTRATOR
3                    true    false      false      NO ACCESS
4                    true    false      false      NO ACCESS
5                    true    false      false      NO ACCESS
6                    true    false      false      NO ACCESS
7                    true    false      false      NO ACCESS
8                    true    false      false      NO ACCESS
9                    true    false      false      NO ACCESS
10                   true    false      false      NO ACCESS
sudo ipmitool user set password 2
Password for user 2: 
Password for user 2: 
Set User Password command successful (user 2)


# IPMI reseten
# https://www.thomas-krenn.com/de/wiki/IPMI_BMC_reset_bei_IPMI_Problemen
sudo ipmitool mc reset cold
# or remote with
ipmitool -I lanplus -H ip_address -U admin -a bmc reset cold

# Wenn das nicht hilft, ggf. hier schauen:
# https://portal.nutanix.com/page/documents/kbs/details?targetId=kA00e000000CrKRCA0

[Shell] User and Group management & File permissions

  • User and Group management
    • id
    • useradd
      • -c – Full name
      • -e – Expiration date
      • -s – Default shell
      • -d – Home directory
    • passwd
    • usermod
      • -l – rename
      • -L – Lock
      • -U – unlock
    • userdel
      • -r – remove user data
    • groupadd
    • groupmod
    • gpasswd [-a -d -A] [user1, user2] [group]
    • newgrp [group]
  • su vs. su – vs. sudo
    • visudo
  • File permissions
    • UGO – User, Group, Other
    • RWX – Read, Write, Execute
    • chmod -R g+x (grant recursive execute permission to group)
      • r = 4
      • w = 2
      • x = 1
      • = 0
      • rwxrwxrwx = 777
      • rw-rw-rw- = 666
      • rwxrwxr–- = 774
      • rw-rw—- = 660
      • rw-r—–- = 640
    • chown
    • chgrp
    • umask

https://www.sluug.org/resources/presentations/2020/2020-02-12_permissions.pdf

[Software] Using pdfunite to merge PDF documents

First install pdfunite:

sudo apt update 
sudo apt install poppler-utils

Syntax:

pdfunite source1.pdf source2.pdf merged_output.pdf

If a pdf file is located in a different folder, you have to add the path like this: $home/Downloads/source1.pdf
If you want to merge all pdf’s of the current folder you cant type:

pdfunite *.pdf merged_output.pdf

An alternative with GUI is PDF Arranger.

[Terminal] Shorcut overview

Further shortcuts:

Ctrl-LCleans the screen
Ctrl-YPastes back the stuff erased by Ctrl-K or Ctrl-U
Ctrl-CAborts a application
Ctrl-ZSuspend a application. Resume it again by fg (resume in foreground) and bg (resume in background).
Use jobs if you have multiple suspended applications and use fg %# (where # is the job number) to get it back on screen or end it with kill %#.
Ctrl-Dis same as typing exit
Pos1like Ctrl-A
Endlike Ctrl-E
Ctrl-RSearch terminal history
Ctrl-GExit searching terminal history

Some of the shortcuts are also recognized by other applications, like Ctrl-U on Ubuntu’s graphical login screen.

[Shell] Delete a folder and its content

If you downloaded a series there are often folders for each episode. Each episode folder often includes another folder called “Sample” with a short demo video file.

Series -> Season 01 -> Episode 01 -> Sample -> sample.mkv

To get rid of these you can use the “find” and “rm” command. To remove each sample folder with its content you have to use the remove command with an “-r”.

find -name "Sample" -exec rm -r "{}" \;

[Shell] SSH Passwordless Login Using SSH Keygen

Generate key, copy key to server and finally ssh passwordless into your server.

ssh-kegen -t rsa
ssh-copy-id root@ip
ssh root@ip

View your generated key with:

cat /home/user/.ssh/id_rsa           #local
cat /home/user/.ssh/authorized_keys  #server

To disable password authentication permanently you have to edit the ssh config. Be sure to first backup before editing. Now just set PasswordAuthentication to “no” in your config and restart the ssh daemon.

cp /etc/ssh/sshd_config /etc/ssh/sshd_config_bak
nano /etc/ssh/sshd_config
service ssh restart

[Shell] zsh-autosuggestions

Simple plugin to get autosuggestions from your history while typing in your Zsh shell. If you are using Oh My Zsh, the installtion is done in 3 steps. Look here.
Just grab the plugin:

git clone https://github.com/zsh-users/zsh-autosuggestions ${ZSH_CUSTOM:-~/.oh-my-zsh/custom}/plugins/zsh-autosuggestions

Add it in your ~/.zshrc (zsh config):

plugins=(zsh-autosuggestions)

And restart the terminal. Done.

[Linux Mint] Install PyWal on Linux Mint 19.2 Cinnamon

“Pywal is a tool that generates a color palette from the dominant colors in an image. It then applies the colors system-wide and on-the-fly in all of your favourite programs.”
For the installation, look at GitHub. In my case, I had to run the following command:

sudo apt purge python3-pip && sudo apt install --install-recommends python3-pip && pip3 install pywal

To get an overview of your PyWal installation, run:

pip3 show pywal

Test it with:

wal -v

If it returns “zsh: command not found: pywal” you have to add the PIP install directory to your path

export PATH="${PATH}:${HOME}/.local/bin/"

To use PyWal, just run it with wal -i and the path to an image.

wal -i /path/to/image.jpg

[Shell] Zsh + Oh My Zsh + Powerlevel10k

Install Zsh (Shell)
https://github.com/robbyrussell/oh-my-zsh/wiki/Installing-ZSH

sudo apt install zsh
chsh -s $(which zsh)

Logout and login back again to use your new default shell.

echo $SHELL

Expected result: /bin/zsh


Install Oh My Zsh (Zsh framework with tools and themes)
https://github.com/robbyrussell/oh-my-zsh

sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"

In addition I installed the Powerline Fonts:

apt-get install fonts-powerline

Restart your terminal to launch the Oh My Zsh configuration.
After the installation and configuration I usually add “neofetch | lolcat” at the end of my zsh config: ~/.zshrc


Install Powerlevel10K (Powerlevel10k is a theme for ZSH)
https://github.com/romkatv/powerlevel10k#oh-my-zsh

git clone --depth=1 https://github.com/romkatv/powerlevel10k.git ${ZSH_CUSTOM:-$HOME/.oh-my-zsh/custom}/themes/powerlevel10k

Set ZSH_THEME=powerlevel10k/powerlevel10k in your ~/.zshrc.

I also installed the patched Meslo Nerd Font and set it as terminal font. Else some icons will not be displayed in Powerlevel10k.
Restart your terminal and go through the configuration steps. The result will look similar to this:

Or like this:

Next you could install a Zsh plugin like: https://nocin.eu/shell-zsh-autosuggestions/

Or check the OMZ Cheatsheet: https://github.com/ohmyzsh/ohmyzsh/wiki/Cheatsheet