Notes about Computers, Computing, Computations, Etc.

1. AltDrag lets Windows 10 have Linux-style “hold down a key and click to move a window” support. 1.48Download
2. Divvy divides up your screen and lets you move windows to different sections with keyboard shortcuts. Download

stable diffusion notes

Some notes_about_ionic.

notes_about_qt

Notes about Yocto

Manipulating Dokuwiki Dates the Hard Way

Publii

Clean up a variety of caches on Windows

Change video container from Matroska (mkv) to mp4 (assuming the video codec is supported by mp4):

ffmpeg -i name_of_input_file.mkv -codec copy output_file.mp4
# If there's issues with the audio codec:
ffmpeg -i name_of_input_file.mkv -c:v copy -c:a aac output_file.mp4

Extract AAC audio from a directory of MP4 files and put them in a folder named audio:

for f in *.MP4; do ffmpeg -i "$f" -vn -c:a copy "audio/$f.m4a"; done

Download a Youtube playlist, keeping only the audio in AAC (.m4a) format:

yt-dlp -f 140 -o "%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s" "https://www.youtube.com/playlist?list=PLaro_mvk6VEkTqkmTcUIvr4MnUzfh434-"

Download a Youtube video in a h264 video and AAC audio:

yt-dlp -f 22+140 https://www.youtube.com/watch?v=cnDJa_HZVP0

To fix photo dates when people email you photos and you need to import them into your photo manager and your photo manager shows all the photos as taken today even though you know they were taken weeks ago but people are so bad at sending photos….

# Inspect the original timestamp
exiftool -r -DateTimeOriginal path_to_picture_folder
# Inspect the modification timestamp
exiftool -r -FileModifyDate path_to_picture_folder
# If FileModifyDate doesn't match what you need, you can set it to the original timestamp
# Note: The double quotes are important so that the shell doesn't think you're redirecting I/O from a file.
exiftool -r "-FileModifyDate<DateTimeOriginal" path_to_picture_folder

Windows lock screen backgrounds don't support tiling so I use ImageMagick to create a large image made of my tiles:

convert -size 2560x1080 tile:image_to_tile.png tiled_img.jpg

moved to its own section

Repack 7zip files as ZIP, requires ``atool`` package to be installed.

arepack -e -F zip *.7z

# Install it
apt install jellyfin
# create symlink because apparently the ubuntu 22.04 package of jellyfin 10.9 is looking at the wrong folder and I don't feel like editing config files.
ln -s /usr/share/jellyfin/web/ /usr/lib/jellyfin/bin/jellyfin-web
 
setfacl  -m g:users:rwX Movies Music MusicVideos YouTube TV\ Shows Audiobooks Workouts Podcasts Rifftrax Books
setfacl -d -m g:users:rwX Movies Music MusicVideos YouTube TV\ Shows Audiobooks Workouts Podcasts Rifftrax Books

Installed LXQt spin of Fedora 41. Some notes and commands:

• I hate Red Hat's installer. It's laid out like some Gnome app and has a terrible workflow.
• Pick the custom partition option (second option, not the Blivet option)
• Set it to LVM, make sure partitions are ext4.
• Enable LUKS encryption
• After boot, update with dnf and reboot.

# We don't want ZRAM swap
dnf remove zram-generator-defaults
 
# Use lsblk to figure out what disk has our encrypted LUKS data
lsblk # in my case it was /dev/sda3
 
# Enroll a FIDO2 key:
systemd-cryptenroll --fido2-device auto /dev/sda3 --fido2-with-user-presence=true --fido2-with-client-pin=true
# you will be asked the LUKS passphrase, and then the FIDO2 key's PIN, and then finally asked to touch the key to confirm presence.
 
# Create a file /etc/dracut.conf.d/fido2.conf with the contents:
add_dracutmodules+=" fido2 "
# the spaces are important - their can't be a space after the += and there should be spaces around fido2
 
# Update with dracut
dracut -f -v   # -v is optional, turns on verbose output.
 
# reboot and see if the FIDO2 key works.

Then install Nvidia driver support

sudo dnf install https://mirrors.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm https://mirrors.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm
 
sudo dnf config-manager setopt fedora-cisco-openh264.enabled=1
 
sudo dnf install akmod-nvidia xorg-x11-drv-nvidia-cuda

Reboot. You may have to add “nomodeset” to the end of the kernel command line if you get a black screen. Need to research if a different parameter is more appropriate.

Run nvidia-smi to make sure your GPU was detected.

Set up old-fashioned swap:

# 32GB swapfile.  We use dd because on file systems like ext4 and xfs, fallocate won't work well.
dd if=/dev/zero of=/swapfile bs=1M count=32768 status=progress
 
# Restrict permissions to root
chmod 600 /swapfile
 
# Initialize swap
mkswap /swapfile
 
# Turn on swap
swapon /swapfile

To automatically enable swap on boot, add this line to your /etc/fstab

/swapfile none swap sw 0 0

Install packages you might need.

dnf install fuse fuse-libs git libxcrypt-compat gperftools

I chose EndeavourOS as my Linux distro to use 100% at home. I have lots of notes at EndeavourOS Setup, some of which may apply to Arch and perhaps even to other distros.

Show bans

fail2ban-client banned

Unban a particular IP

fail2ban-client set apache unbanip 100.19.53.46

mv nextcloud nc-old
mkdir -p ~/nc/29/extracted
cd extracted
unzip ../nextcloud-XX.0.0.zip
mv nextcloud /var/www
cp ncold/config/config.php nextcloud/config/config.php
cd /var/www
chown -R www-data:www-data nextcloud
find nextcloud/ -type d -exec chmod 750 {} \;
find nextcloud/ -type f -exec chmod 640 {} \;
sudo -u www-data php occ upgrade

sudo apt install ubuntu-drivers-common
sudo ubuntu-drivers list --gpgpu
sudo ubuntu-drivers install --gpgpu

Condensed from this ServerFault post:

# Make group for no-net access, add user to group
groupadd no-net
usermod -a -G no-net USERNAME
groups USERNAME
# Rules to allow local network access
iptables -A OUTPUT -m owner --gid-owner no-net -d 192.168.1.0/24 -j ACCEPT
iptables -A OUTPUT -m owner --gid-owner no-net -d 127.0.0.0/8 -j ACCEPT
# Rule to block other network access
iptables -A OUTPUT -m owner --gid-owner no-net -j DROP
# Rule to block outbound IPv6
ip6tables -A OUTPUT -m owner --gid-owner no-net -j DROP
# Create a script called ''no-net'' containing the following two lines:
#!/bin/bash
sg no-net "$@"

There are a couple ways to install Xfce, I prefer the first option:

1. apt install xubuntu-core - perfect; includes whisker-menu for a good application launcher.
2. apt install –no-install-recommends xubuntu-core - boots to GUI, very barebones (not even xfce4-terminal).
3. apt install xfce4 - gives basic installation, still boots to console, so start GUI with startx.

Don't bother with apt install xfce4 –no-install-recommends because apparently installing xorg is just a recommendation, so startx/startxfce will fail :D

# Get rid of cloud init
apt purge -y cloud-init
# Disable IPv6 in the kernel by modifying the CMDLINE options in /etc/default/grub:
GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"
GRUB_CMDLINE_LINUX="ipv6.disable=1"
update-grub
# Edit /etc/default/keyboard to include:
XKBOPTIONS="ctrl:nocaps"

sudo apt install linux-generic-hwe-22.04

Guide to getting Synology ActiveBackup running on Ubuntu 20.04

Settings for a good-looking Xfce4 installation:

• Style: Greybird
• Icons: Elementary Xfce dark
• Window Theme: Arc-dark

On Debian these are installed with: sudo apt install greybird-gtk-theme elementary-xfce-icon-theme arc-theme

Here are some extensive notes on setting this up. I also have a version for CentOS 8 (RIP) but don't maintain/update it.

Notes on setting up Kanboard on Ubuntu.

Sometimes you have to make a program start automatically at boot. Here's how I do it with systemd.

This came up because I was messing with partition layouts for a project and Xfce kept automatically mounting the drives while I was working on them.

# Don't automount drives
xfconf-query -c thunar-volman -p /automount-drives/enabled -s false
# Don't automount media (CDs?)
xfconf-query -c thunar-volman -p /automount-media/enabled -s false

# backup
dd bs=4M if=/dev/mmcblk0 | gzip > /mnt/recovery-usb/backupbot-20210715.img.gz
# restore
gunzip --stdout backupbot-20210715.img.gz | sudo dd bs=4M of=/dev/{whatever the device is}

Add a user: createuser someusername -P

Create a database: CREATE DATABASE somedb OWNER someusername TEMPLATE template0 ENCODING 'UTF8';

GRANT CREATE ON SCHEMA public TO username;

/usr/share/doc/postgresql-common/README.md

# In particular, an LRC lyric file.
sed '1 s/^/\n/' */*.lrc -i

Or realize you made a mistake and don't want newlines at the start of every file.

sed -z -i 's/^\n//' */*.lrc

LC_ALL=C find . -name '*[! -~]*'

From https://www.yiiframework.com/wiki/570/remove-byte-order-mark-bom-from-files-recursively

# Make a list of the files
grep -rl $'\xEF\xBB\xBF' .  | grep .lrc > file_with_boms.txt
# Remove the BOM
while read l; do sed -i '1 s/^\xef\xbb\xbf//'  "$l"; done < file_with_boms.txt