dokuwiki - sysadminery

bash

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

repetition is the key to memory the key to memory. the key to memory. the key to memory. if [ 0 ] then echo "true" else echo "false" fi it makes sense in the context of “if this program runs without error”. but i get tripped in every other context.

docker

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

on debian, docker.io is docker “the debian way” - i.e., dependencies are shareable packages. do not attempt to move docker directory Method 1: -g from you can set the docker directory to another one - but only if that alternate is also on the same filesystem

ffmpeg

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

tl;dr ffmpeg -i input.mp4 -vf scale=320:240,setsar=1:1 output.mp4 ## variables ffmpeg -i input.jpg -vf scale=iw*2:ih input_double_width.png (works on images btw) ## multiple video filters in quotes, separate with comma space: -vf “thing1=whatever, thing2=whateverelse

firefox

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

Custom search engine * about:config * browser.urlbar.update2.engineAliasRefresh = true

grub_rescue

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

so you're in the grub shell, right? “can't find vmlinuz you have to load the linux kernel” or something? ls should show you stuff like (hd0) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) you don't have to include the gpt, going forward. in turn, ls

imagemagick

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

make gif! 50 is ms, loop is times to loop (0 = infinite), dispose previous (must go together) is a necessary thing in giffing if you have transparency, resize with that \> is “only shrink if larger” convert -delay 50 -loop 0 -dispose previous *.jpg -resize

librewolf

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

LibreWolf keepassxc I think librewolf works out of box these days, but if not: cp -r ~/.mozilla/native-messaging-hosts ~/.librewolf/ fingerprinting overrides dark mode, time zones. i know, i know, the point of this is to allow you to blend in with everyone else. so configuring it

linux_boilerplate

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

install * make your password something terrible like “temp” - terminal emulators accept keypresses for weird-ass symbols pretty well, but most things don't cooperate with password managers. * apt-get install sudo * usermod -a -G sudo adam

matrix

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

hold this real quick: register new user ssh in. normally you use register_new_matrix_user, but the digital ocean droplet comes with: ./new-user curl as client you're on port 8448, which is unusual. faq: how do I get an apostrophe? you can just glue strings, be they double-apostrophe or double-quote, together immediately:

nix_misc

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

find, but don't try to find where you obviously can't from find . -type d ! \( -readable -executable \) -prune -o -type f -not -path './.*/*' - UPDATE: broken in current (2026-06-30) debian; still throws a bunch of no-shit-sherlock “errors” in the way.

pi

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

* why are there multiple 5v and multiple 3v pins? consensus online is either “the 5v pins are to power 5v components” or “in case you need them”, so apparently no one else knows, either. * no you can't power a raspberry pi from its 5v rail.

samba

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

sudo smbpasswd -a IF you want to map a samba user to a different local user: edit the file /etc/samba/smbusers = “”

sed

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

escaping check out uptime. Sample output: 11:34:56 up 9 days, 3:24, 5 users, load average: 3.08, 4.04, 14.66 and since I'm sure you forgot: load is “processes waiting for cpu time to execute”, the 3 numbers are “in the last minute”, “

vms

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

virtualbox to qemu/kvm * export a .ova file * extract it like an archive * convert vdi to qcow2 * qemu-img convert -f vdi -O qcow2 debian-kde.vdi debian-kde.qcow2 * macvtap network adapter. (will be hard to get host->guest networking, but meh)

windows

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

new device, immediately reformat Shift+F10 oobe\bypassnr0 disable secureboot: settings -> windows update -> advanced -> recovery -> advanced startup options -> restart now -> troubleshoot -> advanced -> UEFI -> Security reboot into USB: settings

wireguard

Anonymous (anonymous@undisclosed.example.com) — 2026-04-22T07:05:02+00:00

what I've learned: a wg0.conf will have [interface] and [peer]. interface is self, peer is a peer. obv. [peer] will have: * publickey: the public key for the peer. (duh) that implies that each peer needs a [peer] section. * allowed IPs: the _destination_ addresses that the peer in this section can access through you