Start xfce without a graphical manager

cat ~/.xinitrc 

#!/bin/sh
# enable numlock *after* X11 starts

numlockx on &

# start XFCE
exec startxfce4

cat .bash_profile 

#numlockx on &

if [ -z "${DISPLAY}" ] && [ $(tty) = /dev/tty1 ]; then

  startx

fi

ESP8266 serial bridge WIFI to UART

 ESP-01 -> USB-TTL

===================

3v3, EN -> 3V
TX      -> RX
RX -> TX
GND,IO0 -> GND

IO0 -> GND -- programming mode
IO0 -> 3.3V -- normal boot mode

RST - via button - GND - when you press button it resets

It draws around 60-80ma @ 3.3V. Can check the USB to TTL 3.3V regulator on the back for max power. Mine is AMS1117. Can supplu 1A - (1.5A maximum)

sudo apt install esptool

Read chip info:
esptool.py --port /dev/ttyUSB0 flash_id
esptool.py --port flash_id

Output:
Detecting chip type... ESP8266
Chip is ESP8266EX
Detected flash size: 1MB

The cip supports external FLASH via SPI up to 16MB. You can find 1MB or 4MB versions.

Dowload firmware:
https://www.espressif.com/en/support/download/all?keys=8266 pick ESP8266 NONOS SDK
Direct link: https://codeload.github.com/espressif/ESP8266_NONOS_SDK/zip/refs/tags/v3.0.6

extract and go into /bin

esptool.py --port /dev/ttyUSB0 --baud 115200 write_flash \
  --flash_mode dout --flash_size 1MB \
  0x00000 boot_v1.7.bin \
  0x01000 at/512+512/user1.1024.new.2.bin \
  0xFC000 esp_init_data_default_v08.bin \
  0x7e000 blank.bin
  0xfe000 blank.bin

Make a backup:
esptool.py --port /dev/ttyUSB0 read_flash 0x00000 0x100000 esp8266_at_backup.bin
Restore backup:
esptool.py --port /dev/ttyUSB0 write_flash 0x00000 esp8266_at_backup.bin

Connect to ttyUSB0 you can use CuteCom. Use speed 115200 and at INPUT select CR/LF.
Commands: 
https://docs.espressif.com/projects/esp-at/en/release-v2.2.0.0_esp8266/AT_Command_Set/index.html
AT
Ouput: OK

AT+GMR
Output:

AT version:1.7.6.0(Jan 24 2022 08:56:02)␍␊

SDK version:3.0.6-dev(072755c)␍␊

compile time:Jun 17 2024 07:38:00␍␊

Bin version(Wroom 02):1.7.6␍␊

AT+CWMODE?

→ shows current Wi-Fi mode:

• 1 = Station

• 2 = SoftAP

• 3 = Both

Set to ap : AT+CWMODE=1

Scan for networks: AT+CWLAP
Connect: AT+CWJAP="YourSSID","YourPassword"

Show ip: AT+CIFSR

These are saved even on reboot.

Next section must be sent on every reboot:

Step 1 — start a TCP connection to a remote device
AT+CIPMUX=0

AT+CIPSTART="TCP","192.168.1.50",8888

Step 2 — enter transparent (bridge) mode

AT+CIPMODE=1

AT+CIPSEND

Compile and configure ESP3D as a Serial UART to WIFI Bridge

git clone https://github.com/luc-github/ESP3D.git

Configuration before compile:

ESP3D/platformio.ini   --- add to the end of the file

[env:esp01_1m_bridge]

platform = espressif8266@4.1.0

board = esp01_1m

framework = arduino

monitor_speed = 115200

monitor_filters = send_on_enter, colorize, esp8266_exception_decoder

board_build.f_cpu = 160000000L

board_build.f_flash = 40000000L

board_build.flash_mode = dout

board_build.ldscript = eagle.flash.1m.ld

upload_resetmethod = ck

upload_speed = 115200

extra_scripts = pre:platformIO/extra_script.py

build_flags =

    -D ESP3D_BRIDGE            ; enable bridge mode (no web UI)

    -D PIO_FRAMEWORK_ARDUINO_LWIP2_LOW_MEMORY

    -DNONOSDK221=1

    -DNDEBUG

    -DVTABLES_IN_FLASH

lib_ignore =

    ESP32SSDP

    TFT_eSPI

    esp32-usb-serial

ESP3D/esp3d/configuration.h

uncomment and replace xxx with your router data

#define STATION_WIFI_SSID "xxx"

#define STATION_WIFI_PASSWORD "xxxxxxxxx"

Optional if you want better speed

ESP3D/esp3d/src/core/esp3d_settings.cpp

#define DEFAULT_BAUD_RATE "230400"

#define DEFAULT_SERIAL_BRIDGE_BAUD_RATE "230400"

Compile

====

python3 -m venv platformio

source platformio/bin/activate

pip install platformio

cd ESP3D

platformio run -e esp01_1m_bridge --target clean   
platformio run -e esp01_1m_bridge

Upload firmaware

====== dont forget to have IO0 to GND and reset before uploading 

esptool.py --port /dev/ttyUSB0 flash_id

esptool.py --port /dev/ttyUSB0 erase_flash

esptool.py --port /dev/ttyUSB0 write_flash 0x00000 .pioenvs/esp01_1m_bridge/firmware.bin

If you want more speed use a ESP32

git clone https://github.com/luc-github/ESP3D.git

build_flags =

    -DESP_SERIAL_BRIDGE
    -DCONFIG_FREERTOS_HZ=1000

platformio = pio (same command)

pio run -e esp32dev
pio run -e esp32dev -t upload

ESP_LINK for ESP6288

Go to https://github.com/jeelabs/esp-link/releases
Pick latest stable version
You have a Download link of the compiled firmware in the text, NOT in the Assets.

curl -L http://s3.voneicken.com/esp-link/esp-link-v3.0.14-g963ffbb.tgz | tar xzf -

Unzip and Flash:

dout is important and 1MB for the 1mb version ESP-01

esptool.py --chip esp8266 --port /dev/ttyUSB0 --baud 460800 write_flash \

  -fs 1MB -fm dout -ff 40m \

  0x00000 boot_v1.6.bin \

  0x01000 user1.bin \

  0xFC000 esp_init_data_default.bin \

  0xFE000 blank.bin

Then connect to ESP_LINK acces point - access 192.168.4.1 and connect to your AP.

ESP6288 WIFI BRIDGE FOR KLIPPER

phyton3 -m venv platformio

source platformio/bin/activate

pip install platformio

mkdir esp8266_raw_bridge

cd esp8266_raw_bridge

pio init --board esp01_1m

[platformio.ini]

[env:esp01_1m]

platform = espressif8266@4.1.0

board = esp01_1m

framework = arduino

monitor_speed = 115200

upload_speed = 115200

; 1MB flash, safe mode for cheap modules

board_build.flash_mode = dout

board_build.f_cpu = 80000000L

[src/main.cpp]

#include <ESP8266WiFi.h>

const char* ssid     = "YOUR_WIFI_SSID";

const char* password = "YOUR_WIFI_PASSWORD";

WiFiServer server(8888);

WiFiClient client;

void setup() {

  Serial.begin(115200);

  delay(200);

  WiFi.mode(WIFI_STA);

  WiFi.setSleepMode(WIFI_NONE_SLEEP);   // disable WiFi power save (reduces jitter)

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {

    delay(100);

  }

  server.begin();

  server.setNoDelay(true);              // disable Nagle -> lower latency

}

void loop() {

  if (!client || !client.connected()) {

    client = server.available();

    return;

  }

  // TCP → UART

  while (client.available()) {

    Serial.write(client.read());

  }

  // UART → TCP

  while (Serial.available()) {

    client.write(Serial.read());

  }

}

Compile:

pio run -e esp01_1m

Erase flash:

esptool.py --port /dev/ttyUSB0 erase_flash

Upload:

pio run -e esp01_1m -t upload --upload-port /dev/ttyUSB0

Test:

Check router for IP

ping IP

telnet IP 8888

Open serial - I prefer CuteCom GUI, but can use

screen /dev/ttyUSB0 115200

Now type something in telnet and serial, and you should see it on the other side.

Now for KLIPPER
Connect RX,TX and power to ESP6288

Serial to TCP bridge on host running klipper (use your IP)
socat pty,raw,echo=0,link=/tmp/espbridge tcp:192.168.1.176:8888

klipper config:

[mcu]

serial: /tmp/espbridge

Micropython esp32 urequests and TFT

I installed micropython on my esp32 for easier coding - no more waiting for the arduino code to recompile, and easy testing of new code.

All good for now.
A few problems started to appear.
When using a LCD a ST7735 the refresh is very slow, you can see the screen being painted from top to bottom. Its not terrible but not that great, on arduino with C code was fine.

Second problem, when I tried to log some data online with urequest, or even with sockets.
I started to get: OSError: (-29312, 'MBEDTLS_ERR_SSL_CONN_EOF')

The problem comes from SSL part - if the server is using anything more powerfull then RSA for the HTTPS certificate we have a problem.
ESP32 is left with too little memory and cpu from running micropython.

Two solutions.
If you remove the TFT library it works, but this is not really a solution, since I want the data displayed on the screen as well.

I went through the library and started to remove pieces of code not required, like they have 3 functions to initrb, initrg, initrr - to initialize the screen with red, green or blue. Just keep the red one and remove the others.
I also removed the drawing functions like circle, line, rect etc - I only needed text.
After this trimming, I got the first success, urequests actually working, but not all the time.

So second solution was to ditch the HTTPS.
Setup the server to accept http. Then it works fine.

Wifi settings

 Beacon interval - set to maximum to save bandwith and increase battery life.
If you have more Acces Points in the location and need to switch between then lower it, so it will swich faster and not lose the connection.
Also remove other saved networks, as the clients will connect to AP's with lower becon.

DTIM stands for Delivery traffic indication map or message
DTIM - set to maximum for battery save. 

Wifi 5 - ac - 80Mhz channels

Main difference in speed is how many  TX/RX antenas 1x1 or 2x2.
1x1 is 433 Mhz 2x2 is double 866 Mhz. Most mobile devices only have 2x2.

TP-Link Archer C6
5 GHz: 867 Mbps (802.11ac) - means it has 2x2 

Clients example:
Intel Corporation Wireless 7265 - TX/RX Streams 2x2 - 866 Mbps max speed
Intel® Wireless-AC 3165 - Antena 1x1 - 433 Mbps max speed

Wifi 6 - ax  - 960 Mbps only 10% increase in speed vs ac.
Brings 160Mhz channels - but there are only 2 channels in the 5Ghz band
Wifi 6e - ax -  6Ghz band - add much more new bands. So now we can use 160Mhz and get double the speed 1920 Mbps if router supports.

Wifi 7 - be - 320Mhz with even more speed, 3x the ac 866 Mbps = 2598 Mbps

Most router makers dont give the sprecs that really matter directly.

Read more technical data here : https://www.wiisfi.com/

LibreOffice starts very slow on linux

 Uninstall the package xdg-desktop-portal

sudo apt autoremove xdg-desktop-portal

then it will start in second.

Ubuntu / Debian - mirage - image viewer - cannot ratate images.
There is a bug in phyton. Open mirage in cmd and try to rotate a image. You will see the problem.
Solution: sudo apt install mirage/testing.
mirage --version

Bad version: 0.11.1-1+b6 amd64
Good working version: 0.11.2 - found in testing repository

Linux kernel drivers, initrd vs initramfs

The bootloader will load the kernel. This could be GRUB or BCD for windows

 Initrd - meant initial ram disk. Initramfs - initial ram file system.
It detects hawdware and loads drivers. Has all drivers so tjhe kernel image remains small and doesnt cause errors from conflicting drivers, and mount file system (it could be raid, netowork storage etc).
It is big 50MB and contains all drivers. 

initrd - is compressed image. Zstandard compressed data/ ASCII cpio archive
initramfs - uncompressed for older pcs.

It is called initrd in many places although it is a initramfs, particularly in boot loaders, as for them it is just a BLOB. The difference is made by the OS when it boots.

dmesg

systemd-analyze 
systemd-analyze plot > plot.svg

Startup finished in 2.840s (kernel) + 11.378s (userspace) = 14.218s graphical.target reached after 11.364s in userspace

Userspace will be since systemd (init) starts to load services. 
sudo systemctl disable/enable/start/stop NAME_OF_SERVICE

journalctl --disk-usage
journalctl --vacuum-size=50M
journalctl --verify   (verify integrity)

/etc/systemd/journald.conf
SystemMaxUse=50M

Drivers

To use hw (video card, usb device etc) we need 1 or 2 parts depending on the hardware.
1. a device driver that provices software APIs to the kernel to interact with the hardawre and is os kernel specifici - windows/linux, or even different kernel versions, when some major APIs change.

Drivers can be built into the kernel or dynamic loaded. Most are dynamic for the flexibility.
Then there are in tree and out of tree drivers.
If the driver is open source it gets included into the kernel tree and gets re-compiled with every kernel version. If its not open source and its proprietary code, then you have to compile it with every new kernel you install.

Drivers depend on kernel APIs - so if the driver is added to the kernel-tree, when a developer changes the APIs they also update the drivers.
If some older drivers depen on interfaces or APIs that get dropped out the kernel, then they will stop working, and you need to buy new hardware.
Kernel developers work for free and the hardware manufacturers only support old hardware for a few years until they release new hw. None of them will be willing to update the software of old hw.

To some extent this also happens with Windows, as some older hw might only have drivers up to a specific windows kernel versions, lets say only up to windows xp.
But if the driver is proprietary and out the tree, then it will stop working with new kernels - unless someone updates the code, which rerelly happens - so you need to buy new hardware if you want to use the new kernels.

DKMS - Dynamic Kernel Module Support - need to run as root, will automate the rebuild process of external driver modules with every kernel update. 
You need to install it and configure it. --- sudo install dkms

Kernel driver is the one that is bound to the hw.
Kernel modules are different drivers that can be used, if different functionality is required. NVIDIA might provide multiple drivers for different hw accelerated stuff, directx etc.

Modules = driver /usr/lib/modules/6.1.0-15-amd64/

lsmod

modprobe

insmod

rmmod

sudo modinfo  --- module params ex usbcore --- old scheme, new scheme - read first 8bytes or 64bytes to know the speed

Proprietary out-of the tree drivers - Video drivers: 

xserver-xorg-video-intel 

xf86-video-intel 

xf86-video-amdgpu 

nvidia nvidia-utils

sudo apt install xserver-xorg-video-intell

This package provides the driver for the Intel i8xx and i9xx family of chipsets, including i810, i815, i830, i845, i855, i865, i915, i945 and i965 series chips.

2. a firmware - is a piece of code uploaded to the hw chip
In windows the driver includes both of them.
In linux it depends on the open-source license. So in most cases there is a open-source driver included in the kernel -tree and then you might need to get a firmware from the manufacturer.
Most of the time there is a package that it includes it, if not in the main dristo then in a separate repository like nonfree 

In dmesg you can see a driver request a firmware.
Some hw some the firmware written into the chip's memory, and you can make a firmware upgrade, or some hardware use dynamic firmware that is loaded at boot time into the hardware, for ex wifi cards from intel load the firmware dynamic. to install it you use the package iwlwifi - intel wifi lan driver. Even though its called driver it actually contains a firmware

/usr/lib/firmware

The firmware is loaded by udev and sent to the driver - that is a kernel module.
Most of the time kernel modules are drivers. But they can provide other functionality as well, usb stack, network stacks etc.

udev - device manager

DBUS - inter process comunication protocal

***** udevadm monitor

udev rules (1) /lib/udev  --- (2) /etc/udev  --- /usr/lib/firmware

For ttyUSB0 --- sudo usermod -a -G dialout $USER

Edit apt sources and add contrib non-free  

apt search firmware

some example of packages with firmware:

linux-firmware

firmware-linux-free

firmware-linux-nonfree

linux-firmware-nonfree

firmware-iwlwifi

Add driver at debian install time:
Search here:
https://www.debian.org/distrib/packages#search_contents

Put contents in /dev/sdc1/drivers and mount to /lib/firmware

/lib/firmware/iwlwifi-3945-2.ucode

mkdir /lib/firmware

mount /dev/sdc1/drivers /lib/firmware

Printer driver udev config example for a brother printer 

https://wiki.ubuntu.com/Kernel/Firmware

How to compile a linux kernel

Build kernel
============
sudo apt install gcc flex bison libncurses-dev libssl-dev
make xconfig
make menuconfig
/usr/src/linux/.config


make localyesconfig --- local loaded modules --- built-in kernel
make localmodconfig --- local loaded modules --- built as modules
make allnoconfig --- minimum kernel :)
+ [sata + ata + scsi] (ahci - lspci -k) si fs(ext4)

time make -j4 // j3 =j4
make modules
sudo make modules_install --- /usr/lib/modules/xx.xx.xx/
sudo make install --- /boot/

https://www.kernel.org/  download kernel

You can make it in ramdisk - and copy final back to hdd for further changes.

make mrproper- The make mrproper command cleans up any leftover files from previous kernel builds in your source directory. It also wipes out any . config files in your source directory. If you want to do a new clean build.

Boot a Linux MX image to detect all drivers.
ADD all drivers loaded either built into kernel or as modules.

lsmod > /tmp/mylsmod
 make LSMOD=/tmp/mylsmod localmodconfig

Press / and search for ex USB_SERIAL_CONSOLE  for usb to serial driver - and it shows the path where to find it.

TO disable initrd, disable:
General Setup -> at the bottom - initrd imitramfs support
Need to have added as drivers in kernel ext4 and sata/ahci or nvme drivers

For iwlwifi driver to work when built as driver into the kernel you need  to set:
CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
Linux Kernel Configuration

└─> Device Drivers

└─> Generic Driver Options

└─> Firmware loader

└─> Force the firmware sysfs fallback mechanism when possible

No rule to make target 'debian/certs/debian-uefi-certs.pem'
scripts/config --disable SYSTEM_TRUSTED_KEYS
scripts/config --disable SYSTEM_REVOCATION_KEYS

Hardware info

lspci -k

sudo dmesg | grep driver --- to view version

journalctl

sudo dmidecode --mb info

sudo dmidecode -t 16 (max) / 17 (modules) - ram

lm-sensors --- temps/fan/voltages --- sensors

lsusb

lsblk

lshw

uname

lscpu    --- cat /proc/cpuinfo

uname -a --- cat /proc/version --- linux distro version

cat /etc/os-release       --- distro - debian 11 bullseye

Check OpenCL drivers

You can run clinfo (sudo apt install clinfo ) and if it says 0 devices

sudo apt install intel-opencl-icd 

Install grub boot loader + Fix Windows instalation

GRUB (GRand Unified Bootloader)

BIOS will read the first sector of a storage device for a boot partition table.
MBR( master boot record) - 4 partitions
To boot mbr you need UEFI set to boot mode:  Legacy BIOS.

For UEFI - you need a GPT partition table and a fat16/fat32 - mkfs.vfat partition anywhere on the disk  with an EFI folder - 100mb for windows 200mb linux (has all drivers here).

Kernel 10mb + initramfs 75mb ~ 100mb + 30mb windows bcd.
Dont store kernel and initrd here, store them in /boot on the partition you install the linux os.

GPT (Globally Unique Identifier Partition Table) - 128 partitions
EFI partition - FAT16, FAT32 or VFAT

UEFI will look into
<EFI_SYSTEM_PARTITION>\EFI\
Will read folders from here - and display them in UEFI boot menu
Everyfolder must have a xxx.efi boot file

FIX Windows BOOT

The System Reserved partition is optional and is created by the windows setup for the BitLocker only as it stores un-encrypted data in order to decrypt and boot main partition
It also has the BCD (Boot Configuration Data) folder.

To avoid it press SHIFT+F10 at windows setup it opens a cmd :
diskpart
select disk 0
create partition primary
and continue with graphical setup.

Install a boot manager - boot windows install media, press SHIFT+F10 to open a CMD promt

diskpart
select disk 0

list volume

select volume 2 (pick the fat32 one)

assing letter k:

exit

Create a BCD store. - required to boot windows.

bcdboot c:\Windows /l en-GB /s K: /f ALL

Bcdboot.exe c:\windows /s c:

 
/s k: = install to k:

Grub doesnt see ext4 unknown filesystem --- remove metadata_csum

sudo dump2fs /dev/sda1 | head -20

install package e2fsprogs

sudo tune2fs -O ^metadata_csum /dev/sda1  -- remove

sudo tune2fs -O metadata_csum /dev/sda1  -- add

sudo e2fsck -f /dev/sda1

Edit grub on windows

open diskpark - type ar run or cmd
list volume
select volume 1
assign letter=z

You will get access denied efi partition windows when you try to access the partition.
Right click on start menu - and select PowerSheel (admin)
Type z:  then use cd and ls to navigate
To edit grub.cfg type notepad grub.cfg at the proper path

remove letter=z in diskpart again to remove it from explorer

Install GRUB

mount /dev/xxx /mnt  --- efi partition

--boot-directory=/mnt -- it will install under /mnt/grub - grub files
--efi-directory=/mnt -- it will install under /mnt/EFI/os_name (Microsoft/Debian/Ubuntu etc)

grub-install --boot-directory=/mnt/linux/boot --efi-directory=/mnt/linux/boot/efi --target=x86_64-efi
grub-mkconfig > /mnt/grub/grub.cfg

grub-update is equivalent to grub-mkconfig

grub-mkconfig -o /boot/efi/EFI/grub/grub.cfg

ls 

grub> ls (hd1,gpt3)/
grub> set root=(hd0,1) grub> linux /boot/vmlinuz-3.13.0-29-generic root=/dev/sda1 grub> initrd /boot/initrd.img-3.13.0-29-generic grub> boot

optional (insmod part_gpt, insmod chain)
set root=(hd0,gpt1)
use tab after / or after each folder to explore contents - bootmgr is for bios, bootmgfw.efi for uefi.
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
boot

Grub: no suitable video mode found boot in blind mode
insmod all_video

Edit grub.cfg :

insmod all_video

insmod part_gpt

insmod ext2

insmod gzio

insmod gfxterm

insmod gettext

font=unicode

set gfxmode=auto

set lang=en_US

set timeout=5

set menu_color_normal=cyan/blue

set menu_color_highlight=white/blue

# For booting Microsoft Windows
menuentry "Microsoft Windows 7" {
    set root=(hd0,2)
    chainloader +1
}

menuentry 'Debian' {

set root='hd0,gpt2'

echo 'Loading Linux ...'

linux /boot/vmlinuz-5.10.0-11-amd64 root=/dev/sda2 ro

echo 'Loading initial ramdisk ...'

initrd /boot/initrd.img-5.10.0-11-amd64

}

menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {

fwsetup

}

Manual boot from GRUB menu

chainloader /efi/Microsoft/Boot/bootmgfw.efi
boot

iso images:

loopback lo (hd0,4)/image.iso

linux (lo)/artix/vmlinuz boot=casper iso-scan/filename=${isofile}
initrd (lo)/artix.initrd.gz

boot

ls - shows disks
ls (hd0,1)/    +tab = browse partitions

If you get to grub boot menu grub 0.x

root (hd0,0) --- this will mount the partition

kernel /boot/vmlinuz... root=/dev/sda1

initrd /boot/initrd....

boot

Grub 2

ls

set root=(hd0,msdos1)

linux /boot/vmlinuz... root=/dev/sda1

initrd /boot/initrd...

boot

Grub custom font

# Generate a GRUB-compatible font with specified size
# from a TTF (type-type font)

sudo grub-mkfont --output=/boot/grub/fonts/DejaVuSansMono36.pf2 --size=36 /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf

Slow loading of linux from USB on old laptops

Grub calls the BIOS to read from the USB.
Some usb sticks are not compatible with bios drivers for high speed usb. Other sticks might work at faster speeds.
 

 Grub uses bios driver to load vmlinuz and initramfs from usb and it is using USB 1.0 - it has a speed of around 1.5Mbps = 0.2MB/s. 75mb/0.2 = 375 = 5-10 min.

For old laptops / pcs:

The Plop Boot Manager is a small program to boot different operating systems.
The boot manager has a built-in ide cdrom and usb driver to access that hardware without the help/need of a bios.

https://www.plop.at/en/bootmanager/intro.html

Connect to Wifi internet linux

echo 127.0.0.1    laptop > /etc/hosts
echo pcname > /etc/hostname

Connect to WIFI

sudo systemctl enable iwd

Enable dhcp client

/etc/iwd/main.conf

[General]

EnableNetworkConfiguration=true

[Rank]

BandModifier5Ghz=100.0

DNS

Either use resolv.conf for a static dns or enable systemd-resolved

/etc/resolv.conf

nameserver 1.1.1.1

#cloudflare

nameserver 4.4.4.4  

nameserver 8.8.8.8

# google public dns

/etc/runit/sv/iwd/run

#!/bin/sh

exec /lib/iwd/iwd 2>/dev/null

ln -s /etc/runit/sv/iwd /run/runit/iwd

Connect to AP

rfkill 

rfkill unblock all

* if it is powered off - press FN+Wifi or Fn+Airplane Mode twice

iwctl device list

iwctl station wlan0 scan

iwctl station wlan0 get-networks

iwctl station wlan0 connect NETWORK_NAME

iwctl station wlan0 disconnect

iwctl station wlan0 show

iwctl known-networks list

iwctl known-networks NETWORK_NAME forget

Install iwgtk. On debian it must be compiled.

ifconfig - temporary settings in kernel, not persistent at reboot

ifup/down - config /etc/network/interfaces

Don't install networkmanager 
If you do, sudo systemctl disable NetworkManager-wait-online
Systemd - waits for - multi-user environments - for the network to connect and then continues to load services and you get a long wait at boot.

===========================

ip a

dhclient -v eth0

route

ping

netstat -tapn

namp

iptables -L (INPUT - FORWARD - OUTPUT)

wpa_supplicant

wpa_password wifi_network password > wifi

ip a
rfkill -- check it is enabled

wpa_supplicant -B -i wlan0 -c ./wifi

sudo dhclient wlan0

wpa_supplicant -B -i wlan0 -c <(wpa_passphrase "Your_SSID" Your_passphrase) && dhclient wlan0

Link service to runit by 

# ln -s /etc/sv/wpa_supplicant /var/service

or systemctl enable wap_supplicant

Manual install debian or arch linux from scratch

Boot  Arch linux image from USB. Use rufus to burn it windows, balenaetcher or dd in linux.
dd if=~/Download/arch.iso of=/dev/sdb bs=1M status=progress oflag=direct

* Install base packages distro

Wifi - internet

iwctl station wlan0 connect SSDID_name

Partition

lsblk
cfdsik -> sda1 100-200MB efi , sda2 20GB

mkfs.ext4 /dev/sda2
mount /dev/sda2 /mnt/linux

Install:
- from arch: pacman -Sy debootstrap
- from debian: apt install debootstrap arch-install-scripts

Install debian: debootstrap --arch amd64 stable /mnt/linux

genfstab /mnt/linux >> /mnt/linux/etc/fstab
Chroot into the new install
arch-chroot /mnt/linux     --- this will auto mount /dev /proc etc from current system

[manual without arch-chroot]
sudo mount -t proc /proc /mnt/linux/proc
sudo mount -o bind /dev /mnt/linux/dev
sudo mount -o bind /sys /mnt/linux/sys
chroot
[/manual]

Set Time Zone:
ln -sf /usr/share/zoneinfo/Europe/Bucharest /etc/localtime
date

apt install sudo
passwd   --- create password for root or you cant login after reboot

adduser username

usermod -aG sudo user

Kernel

apt install linux-image-amd64

or 

copy /boot/vmlinuz 
copy /usr/lib/modules/uname -r/ /mnt/linux/.... same path

Install GRUB
mount /dev/sda1 /mnt/efi
grub-install --boot-directory=/mnt/efi --efi-directory=/mnt/efi --target=x86_64-efi

ln -s /boot/vmlinuz-xxxx vmlinuz
ln -s /boot/initrd-xxxx initrd

nano /mnt/efi/grub/grub.cfg

menuentry 'Linux' {

    set root ='hd0,gpt2'

    linux    /boot/vmlinuz root=/dev/sda2 ro

    initrd    /boot/initrd

}

WIFI

nano /etc/apt/sources.list - add non-free-firmware
apt update
apt install firmware-misc-nonfree    --- othter wifi boards - realtek asus
apt install firmware-iwlwifi    --- mostly intel wifi boards

apt install iwd (alternative is wpa_supplicant)

Enable dhcp client + dns

/etc/iwd/main.conf

[General]

EnableNetworkConfiguration=true
/etc/resolv.conf
nameserver 1.1.1.1

nano /etc/hostname

nano /etc/hosts    - 127.0.0.1 hostname

Reboot

sudo dpkg-reconfigure locales

* Video system

You can install here a desktop/login manager - gdm3, lightdm etc OR just use xinit without an GUI interface

apt install xfce4   --- it will install xorg as a requirement

Xwayland works with gdm3 and gnome only for now.
Xfce4 works with lightdm and xorg/x11.

Change active Display Manager:
sudo dpkg-reconfigure gdm3
sudo dpkg-reconfigure lightdm

To start video mode:
systemctl start lightdm 

sudo apt install wget
wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
dpkg -i google.....deb

sudo apt -f install  --- to fix dependencies error from above

Change console FONT size

Go to directory /usr/share/kbd/consolefonts - and ls to see all available fonts

then setfont iso01-12x22.psfu.gz 
or any other fonts you like from there

dpkg-reconfigure console-setup

https://www.linuxfromscratch.org/

ArchLinux - https://wiki.archlinux.org/title/Installation_guide

https://gist.github.com/myTerminal/4f1d26eaf32cdc5bcc9fb19f594c03d2

https://www.debian.org/releases/stretch/amd64/apds03.html.en

https://wiki.debian.org/Debootstrap

On xfce4 time will not update after sustend on the gui - but time sync works fine

Storage partitions under linux - swap - ramdisk

Partitions

gparted, cfdisk, lsblk, df -h

mkfs.ext4 /dev/sda2 , mkfs.ntfs etc --- format the partition  

sudo fdisk -l     --- view disks
lsblk -f     --- view disks and filesystems
sudo blkid - partition UUID
df -h
df -ih --- innodes

sudo tune2fs -l /dev/sda8
sudo tune2fs -m 1 /dev/sda8
Reserved blocks for root - so when you run out of space you can still login. Set default to 5% of partition size..
*** merge online cu partitia mounted = ok
After you rezise partition size with cfdisk you need to also resize the filesystem:
sudo resize2fs /dev/sdb

Mounting

/mnt : Mount point for a temporarily mounted filesystem - should not have subfolders
/media : Mount point for removeable media

These 3 are required for chroot, 

are interfaces to kernel data structures and not real files on hdd - they stay in ram.

Can check with the command findmnt /sys
/dev - file devices
/proc - running process table + some system info same as sys left for backward compatibility 
/sys - hardware information

/run - virtual ram runtime for udev - needed before /var/run is mounted

/etc - system config files - before changes would be done in source code and recompile
means etcetera - as in the rest of the files of a system

/var - variable stuff like logs
/opt - optional software not installed with system package manager
/usr - libraries, binaries, manuals - all the software

/etc/fstab --- automount at start-up - should at least have /

mount -a --- mount all from fstab

UUID=14D82C19D82BF81E /mnt/d auto nosuid,nodev,nofail,x-gvfs-show 0 0

1. partition id
2. mount point
3. partition type 
4. options

nosuid - specifies that the filesystem cannot contain set userid files. This prevents root escalation and other security issues.
nodev - specifies that the filesystem cannot contain special devices (to prevent access to random device hardware).
nofail - removes the errorcheck.
x-gvfs-show - show the mount option in the file manager. If this is on a GUI-less server, this option won't be necessary.
0 - determines which filesystems need to be dumped (0 is the default).
0 - determine the order in which filesystem checks are done at boot time (0 is the default).

mount /dev/sda1 /mnt

NTFS partition from windows closed without proper shutdown ---> ntfsfix /dev/sda1

If that doesn't work you need to boot a windows os and it will fix it. ntfs is not opensource.

See mounted filesystems and space usage : 

du -sh -- file/folder size

INODES on linux

The file system has an inode table - every file and directory on a disk requires one inode entry.

To have more inode you need to re-format the filesystem and reserve more space for the inode table.

Other filesystems dont allocate a fixed inode table like XFS, JFS, BtrFS or ZFS.

On ext3 and ext4 - the most common used filesystems on linux you get by default 1 inode for every 16kb of space.
using the -i flag to mkfs.ext4 to specify the bytes:inode ratio. 

This problem is most common on servers where you can get a lot of small files.
Apache’s disk cache system (mod_cache_disk) - creates a lot of small files - htcacheclean should clean it.

Swap

Instead of storage swap partition you can have a swap partition in ram.
Of course this will not work for hibernation.

Swap file

dd if=/dev/zero of=/swapfile bs=1M count=3064 status=progress
chmod 600 /swapfile
mkswap -U clear /swapfile
swapon /swapfile
Add it to fstab
/swapfile none swap defaults 0 0 >> /etc/fstab

Ram swap

When ram gets full, data is moved and compressed into this z swap partition.

To enable it, open a cmd and create these files :

sudo su
echo zram > /etc/modules-load.d/zram.conf
echo 'options zram num_devices=1' > /etc/modprobe.d/zram.conf
echo 'KERNEL=="zram0", ATTR{disksize}="512M",TAG+="systemd"' > /etc/udev/rules.d/99-zram.rules

touch /etc/systemd/system/zram.service

[Unit]
Description=Swap with zram
After=multi-user.target

[Service]
Type=oneshot
RemainAfterExit=true
ExecStartPre=/sbin/mkswap /dev/zram0
ExecStart=/sbin/swapon /dev/zram0
ExecStop=/sbin/swapoff /dev/zram0

[Install]
WantedBy=multi-user.target

sudo systemctl enable zram
reboot 

swapiness - sudo nano /etc/sysctl.conf

The default value is 60."
0 - does not disable swap

To use a swap partition instead

# mkswap /dev/sda5
# sync
# swapon /dev/sda5

Ram-disk

For windows :
The only free software that allows for more then 4gb is ImDisk Toolkit

For linux  :
First check how much ram you got : free -h
Make a new directory and mount the ramdisk :

sudo mkdir /mnt/ramdisk
sudo mount -t tmpfs -o size=10g tmpfs /mnt/ramdisk
tmpfs - is mounted in ram
To make it available every time you boot edit /etc/fstab :

tmpfs       /mnt/ramdisk tmpfs   nodev,nosuid,noexec,nodiratime,size=1024M   0 0

Android on linux

 ADB - Android Debug Bridge - sudo apt install adb

To enable go to Settings - About phone - scroll to bottom - tap many times - Build number - until you get a message Developer mode enabled.
Now go to Settings - Developer mode - enable USB DEbugging

Connect android via usb to computer - you will get a message to allow connection.

sorin@hp250:~$ adb devices
List of devices attached
ZY326M79LR device

sorin@hp250:~$ adb tcpip 5555
restarting in TCP mode port: 5555

sorin@hp250:~$ adb connect 192.168.0.201:5555
connected to 192.168.0.201:5555

sorin@hp250:~$ adb devices
List of devices attached
192.168.0.201:5555 device

Then use scrcpy (sudo apt install scrcpy ) to connect to the phone from laptop.
Record screen with OBS Studio - and select scrcpy window.

DroidCam - use camera

Convert scanned document images to pdf

Rename the images with numbers 1, 2 ,3 etc 12.jpeg - the image view/print app from windows doesnt use the same order as you see it in explorer.

Select all scanned images, right click - Show more options - Print

Select Print to PDF, go to Options - Printer Properties -> and select Orientation - Portrait

Linux autologin + Sudo with yubikey

Authentification is done by PAM - Pluggable Authentication Modules
Passwords are stored in /etc/shadow

passwordless login with yubikey on linux

HMAC-SHA1 Challenge-Response is specific for Yubikey only.

yubiko-pam - is yubikey-specific and relay on it's specific features, 

pam-u2f - is generic and works with any keys supporting u2f and/or fido2.

auth required pam_u2f.so cue interactive

 Set authentification with yubikey off-line with Challenge-Response so you dont have to type a password just touch the keyyubikey

install yubico pam package
# install chalenge to slot 1
# generate challenge file for slot 1
ykpamcfg -1 -v
man ykpamcfg

/etc/pam.d/common-auth

#[success=1 new_authtok_reqd=ok ignore=ignore default=die]

auth required   pam_echo.so "Touch the key"

auth  sufficient      pam_yubico.so mode=challenge-response authfile=/home/user/.yubico/challenge-xxxx

Install xscreensaver if you want to lock the screen

Autologin with desktop/login manager

autologin with lightdm:
/etc/lightdm/lightdm.conf -- uncomment the lines

autologin-user = sorin

autologin-user-timeout = 0

*Note if you cannot login with the user but you can with root check if you ran out of space. (df -h)

Autologin with systemd directly

Agetty is called by /bin/INIT and this calls /bin/login 

/etc/systemd/system/getty.target.wants/getty@tty1.service

add -a my_username

ExecStart=-/sbin/agetty -a username - $TERM
remove the login options -o '-p -- \\u'

To start X11 with xfce

~/.bash_profile

if [ -z "${DISPLAY}" ] && [ $(tty) = /dev/tty1 ]; then

  startxfce4

fi

Mouse latency response time in linux

 lsusb

Find your mouse. 

Bus 001 Device 003: ID 1a7c:0191 Evoluent VerticalMouse 4

sudo usbhid-dump -s 1:3 -f -e stream

From the manual we get what the parameters mean:

man usbhid-dump

 -s =bus[:dev]

Replace -s 1:3 with the Bus Device for your device

Output is in the form

BUS:DEVICE:INTERFACE:ENTITY TIMESTAMP

.001:003:000:STREAM             1667902900.482858

 00 00 00 FC FF 00 00

.001:003:000:STREAM             1667902900.490787

 00 00 00 FE FF 00 00

.001:003:000:STREAM             1667902900.498863

 00 01 00 FC FF 00 00

Timestamp is in seconds before the point and subdivisions of seconds after the point.
First 3 digits milliseconds next 3 digits microseconds.
So the difference between two events is in my case is 8ms.

Note the speed dpi choise does not affect this. This is the maximum physical transmit speed.

usbhid-dump will disconect you mouse/device.
if you mess up just remove the receiver and plug-it back in or wait 60 seconds.

It is a WiFi Evoluent Vertical Mouse 4.

Configure Mouse Buttons X11

xinput

press a button and run in terminal to find the number associated with each button

xinput query-state id-nr

or

xev | grep button

xinput set-button-map "Kingsis Peripherals Evoluent VerticalMouse 4" 1 2 3 4 5 6 7 9 2 8

90-evoluent.conf /usr/share/X11/xorg.conf.d/conf

Section "InputClass" Identifier "Evoluent VerticalMouse 4" MatchUSBID "abcd:0123" # input id: 1 2 3 4 5 6 7 8 9 10 Option "ButtonMapping" "1 2 3 4 5 6 7 9 2 8" EndSection

Nofap - block porn

 Change the dns on your router in the DHCP section, with the dns from cisco OpenDNS  FamilyShield

https://www.opendns.com/setupguide/#familyshield

208.67.222.123
208.67.220.123

Use cloudflare warp - set it to familly mode full (malweare + adult)

Chrome - uses and external google dns to bypass it.
chrome://net-internals/?#dns  --- you can check here what dns record it returns

To disable external google dns go to:

Settings - Privacy and security - Security : chrome://settings/security - 
at the bottom of the page Use secure dns - With your current service provider - and it will use warp/cloudflare settings.

Youtube - click the profile picture in right top corner - and select Restrcited Mode - On - but the downside is it disables the comment section.

Android - Settings - Google  - Settings for Google apps (last one) - Search, Assitant & Voice (last one) - Hide Explicit results - On