• Archives

    1 min read · archives backups

    Create Combine many files and directories into a single t-archive file. 1tar cf "${archive}".tar ${dir} You can remember this with the mnemonic 'Create File'. Unfortunately, this stores the full file path, so making a tar archive of /etc/nginx/ will store etc/nginx (without the leading /). It's often better to tell tar …


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  • at

    1 min read · basics time

    Install with: 1sudo apt install at Enable the daemon service with: 1sudo systemctl enable --now atd Then jobs can be specified with absolute time, such as: 1at 16:20 1at noon 1at midnight 1at teatime Type in your command, e.g.: 1touch /tmp/$FILE.txt The jobs can also be specified relative to the current time: 1at now …


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  • autologin

    1 min read · distros arch

    Automatic Login Edit /etc/systemd/system/getty@tty1.service.d/override.conf by typing: 1sudo systemctl edit getty@tty1 The put in the following, changing [ USER ] to your username. [Service] ExecStart= ExecStart=-/usr/bin/agetty --autologin [ USER ] -s %I 115200,38400,9600 vt102 Automatically Start X In .bashrc. 1 if [ …


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  • awk

    2 min read · system csv

    Basics See a file's contents: Return full contents of a string: 1awk '{ print }' file Print the first and second column: 1awk '{print$1$2}' Return every line with the word 'the' (like grep): 1awk '/the/{print}' file Print everything containing a lowercase letter: 1awk '/[a-z]/{print}' file Same with numbers [0-9], or …


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  • Base 16

    1 min read · data

    Base 16 numbers often use 0x at the start, so '10' just means '10', but 0x10 means '10 in base 16' which means '16'. For small numbers, use printf. 1printf "%x" $NUMBER For any number, use bc. 1fortune | md5sum | cut -d' ' -f1 | tr [:lower:] [:upper:] | bc Inputting base 16 uses ibase=16. Outputting base 10 uses …


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  • bash games

    1 min read · fun

    Games are a great way to learn bash. mapscii.me is an interactive terminal map. Install telnet. telnet mapscii.me Over the Wire teaches bash with small challenging you can do over ssh. Doom! Try it online with telnet doom.w-graj.net 666.


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  • Bash tips

    1 min read · shell comfy bash

    This & That Refer to 'that last thing', and 'the first thing': 1fortune -l > file1 2cat !$ | tr -d u > file2 3cat file1 !$ 4diff !^ !$ NB: this can go wrong: 1ls -l file1 file2 2cat !^ NB: this only works when running bash interactively, never in scripts. Lists You can put a list inside any bash argument, and bash will …


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  • Basic Sound

    1 min read · sound

    Pulse If you have pulse, use pulse. Check with which pulseaudio. No output means you need to use alsa (below). Volume Control 1pactl set sink @DEFAULT_SINK@ +5% Find working outputs: 1aplay -l #Sound Settings Surround.5 seems best. Find what Sound settings exist amixer scontrols Change a Sound setting 1amixer set …


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  • Block Automatic SSH Attacks

    1 min read · networking system Setup ssh security

    Requirements ssh Install fail2ban. Copy a jail configuration file to make your SSH jail.1 1sudo fail2ban-client status 2cd /etc/fail2ban/ 3less jail.conf 4cat << EOF > jail.d/ssh.local 5[sshd] 6enabled = true 7 8ignoreip = 127.0.0.1/8 ::1,192.168.0.0/16 ::1 9EOF 10 11sudo systemctl enable --now fail2ban 12sudo …


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  • Board Games with Recfiles

    1 min read · data recfiles games

    Requirements Recfiles You can play with a board games database from boardgamegeek.com. Download the Database 1mkdir board_games 2cd board_games 3curl -Lo bg.zip 'https://www.kaggle.com/api/v1/datasets/download/threnjen/board-games-database-from-boardgamegeek' 4unzip bg.zip The header line shows fields with a bunch of …


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