A hard link is one file which exists in multiple locations. Each file has an ID, which is kept on the hard disk's partition. Each hard link has the same ID, because they are the same file. This ID is called the 'inode'. Create a file, and a hard link: 1fortune > $file_1 2mkdir -p x/y/z/ 3ln $file_1 x/y/z/$file_2 Have a …

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Uninstall vim. Install vi. Write a few blog posts. The ancient wisdom is correct - everyone should start with vi. But the standard wisdom fails to mention writing. So people just 'try to remember', then they edit a couple of configuration files with vim, then stop, because it's a pain to think about keystrokes while …

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Analyse json easier with ijq. 1column -J -ts: -H PW,GID,shell -N User,PW,UID,GID,Description,Home,shell /etc/passwd > host.json 2ijq !$ If you get stuck, try adding .[].

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Convert jpg to png. 1magick image.jpg image.png 1magick image.jpg -quality 50 image.jpg 'Quality' must be from 1 to 100. 1magick -resize 50% image.jpg image2.jpg Resizing only changes jpegs. Change a png with: 1magick input.png png8:out.png Invert Colours 1magick input.jpg output.jpg -negate Make Images Smaller 1magick …

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Keyboard layout changed. 1ls /usr/share/kbd/keymaps/**/*.map.gz 1loadkeys uk.map.gz Check if boot mode is UEFI 1ls /sys/firmware/efi/efivars Without efivars, the system must boot with BIOS. Check network's up 1ping archlinux.org Set system clock properly 1timedatectl set-ntp true Check disks 1lsblk Make partition …

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1pacman --sync --noconfirm --needed base-devel gcc git 2git clone https://aur.archlinux.org/yay.git /tmp/yay 3makepkg -C !$ -si The flags are mostly the same as in pacman. But running yay without flags will do the update like yay -Syu and with package name it will search packages in the AUR and pacman repos, and let …

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Want to find and replace, but also confirm each instance? 1vim -c "%s/${pattern}/${replacement}/gc" -c 'wq' ${file} Notice that double-quotes (") in the first command (-c). Alternatively, check with an example string: 1sed "s/${pattern}/ARGLEBARGLE/g" ${file} | grep 'ARGLEBARGLE'

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Download the Database Download the csv data, and separate the ipv4 data from the ipv6. 1curl -Lo ips.zip 'https://www.kaggle.com/api/v1/datasets/download/ipinfo/ipinfo-country-asn' 2unzip -p ips.zip country_asn.csv | csv2rec | recsel -e "start_ip ~ '.'" > ipv4.rec 3unzip -p ips.zip country_asn.csv | csv2rec | recsel …

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Intro This is a basic Linux firewall program. Look at your firewalls: 1iptables -L We see the output of input, output and forwarding rules. Forward I don't need any forwarding, so I'm going to drop all forwarding: 1iptables -P FORWARD DROP Input Let's 'A'dd, or 'A'ppend a rule with -A. Let's drop all input from a …

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Jenkins on Void Jenkins is janky. Start Start the service file. 1su root 2ln -s /etc/sv/jenkins /var/service 3sv start jenkins Then visit the web interface with $BROWSER localhost:8080. If it's not working, try running the command from the run file the first time: 1chpst -u jenkins java -jar /opt/jenkins/jenkins.war …

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