General Linux and other related stuff

0-INDEX

My general experiences about GNU/Linux distro's and other stuff

adblock-script

#!/bin/bash
set -o nounset
set -o errexit

###############################################################################
##### This script will generate an IPv4-only hosts file that blocks domains
##### responsible for advertisements, analytics, and malicious activities
#####
##### Modified from: https://github.com/fr0stycl34r/update-hosts
###############################################################################


## We must be root in order to modify the contents of /etc
rootcheck() {
  if [[ $UID -ne 0 ]]; then
    echo "Please run this script as root"
    exit 1
  fi
}
rootcheck


## Backup the current hosts file
mv /etc/hosts /etc/hosts.bak


## Create a temporary file to dump the various lists into
temphosts=$(mktemp)


## Download various pre-made lists into our temp file
wget -nv -O - http://someonewhocares.org/hosts/hosts >> $temphosts
wget -nv -O - http://winhelp2002.mvps.org/hosts.txt >> $temphosts
wget -nv -O - http://www.malwaredomainlist.com/hostslist/hosts.txt >> $temphosts
wget -nv -O - http://adblock.gjtech.net/?format=hostfile >> $temphosts
wget -nv -O - http://hosts-file.net/ad_servers.asp >> $temphosts
wget -nv -O - "http://pgl.yoyo.org/adservers/serverlist.php?hostformat=hosts&showintro=0&mimetype=plaintext" >> $temphosts


## Cleanup the list; remove commented lines, remove duplicates, etc
sed -e 's/\r//' -e '/^127.0.0.1/!d' -e '/localhost/d' -e 's/0.0.0.0/127.0.0.1/' -e 's/ \+/\t/' -e 's/#.*$//' -e 's/[ \t]*$//' < $temphosts | sort -u > /etc/hosts


## Append some necessary stuff to the beginning of the file
echo "# Last updated on $(date)
127.0.0.1 localhost
127.0.0.1 $HOSTNAME" | cat - /etc/hosts >> temp && mv temp /etc/hosts


## A bit of cleanup
rm $temphosts

adduser

Adding users and creating a home directory
------------------------------------------
useradd <name>
passwd <name>

mkdir /home/<name>
chown <name>:users /home/<name>

arch-install

https://wiki.archlinux.org/index.php/Beginners%27_guide
timedatectl set-ntp true
timedatectl status

Partitioning
------------
parted -a optimal /dev/sdb
print

# check if NO partition
# if partition
rm [partition number]

mklabel gpt
mkpart primary 1MiB 3MiB (bios partition)
name 1 grub
set 1 bios_grub on
mkpart primary ext4 3MiB 100MiB (/boot partition)
name 2 boot
set 2 boot on
mkpart primary 100MiB 2150MiB (swap partition)
name 3 swap
mkpart primary ext4 2150MiB 100%
name 4 rootfs
print

# ignore lba

quit
mkfs.ext4 -L "boot" /dev/sdb2
mkfs.ext4 -L "rootfs" /dev/sdb4
mkswap -L "swap" /dev/sdb3
swapon /dev/sdb3
mount /dev/sdb4 /mnt
mkdir -p /mnt/boot
mount /dev/sdb2 /mnt/boot

Install & Configure Arch
-------------------------
pacstrap /mnt base base-devel vim
genfstab -U -p /mnt >> /mnt/etc/fstab
arch-chroot /mnt /bin/bash
vim /etc/locale.gen

# uncomment en_US.UTF-8 UTF-8, as well as other needed localisations
:wq

locale-gen
echo LANG=en_US.UTF-8 > /etc/locale.conf
tzselect
ln -sf /usr/share/zoneinfo/Europe/Brussels /etc/localtime
hwclock --systohc --utc
vim /etc/mkinitcpio.conf

# change HOOK order (HOOKS = "base udev autodetect modconf block filesystems keyboard fsck")
/HOOKS
HOOKS = "base udev block autodetect modconf filesystems keyboard fsck"
:wq

mkinitcpio -p linux
pacman -S sudo
EDITOR=nano visudo

# uncomment "%wheel ALL=(ALL) ALL"
Ctrl+O
Ctrl+X

pacman -S grub [os-prober] (search for other operating systems)
grub-install --recheck /dev/sdb
grub-mkconfig -o /boot/grub/grub.cfg
echo archpleb > /etc/hostname
systemctl enable dhcpcd@enp2s5.service

(Wireless):
pacman -S iw wpa_supplicant dialog

passwd
exit
umount -R /mnt
reboot

useradd -m -g users -G wheel,storage,power,audio,video -s /bin/bash pleb
passwd pleb

Installing basic stuff
-----------------------
pacman -S alsa-utils alsa-tools pulseaudio pulseaudio-alsa
pavucontrol ttf-dejavu samba smbclient networkmanager networkmanager-vpnc
networkmanager-pptp networkmanager-openconnect network-manager-applet gvfs gvfs-smb sshfs
systemctl enable NetworkManager

reboot

Install XFCE desktop environment
---------------------------------
https://wiki.archlinux.org/index.php/Xorg (info about graphic cards)

pacman -S xorg-server xorg-server-utils xorg-xinit xorg-utils
pacman -S xfce4 xfce4-goodies gamin firefox
cp /etc/X11/xinit/xinitrc ~/.xinitrc
vim ~.xinitrc

# Comment existing exec and add
exec startxfce4

startx

Install LightDM login manager
-----------------------------
pacman -S lightdm lightdm-gtk-greeter
systemctl enable lightdm.service

Arduino Uno

Using the Arduino with "Arduino IDE" or "Processing"
----------------------------------------------------

Default you don't have access to the Arduino.
Because you need to be root.
But this is not a good solution.
If you program as root, all your projects will be owned by user "root".
Which is not what you want because this will cause even more problems.

My solution to this is just.
Change the rights, but TEMPORARY!
Just change the access rights when you use the Arduino.
Before changing the rights.
I first checked what are the default rights. (/dev/ttyACM0) chmod 660.
To make things simple I just change the rights to chmod 777.
Granting all users full access, which should solve everything.
But before I disconnect and after I don't need it anymore.
I put the default access rights back to normal chmod 660.

BSD-Packages

pkg check -> Sanity checks installed packages.
pkg clean -> Cleans the local cache of fetched remote packages.
pkg delete -> Delete a package from the database and the system.
pkg fetch -> Fetches packages from a remote repository.
pkg install -> Install a package from a remote package repository.
pkg plugins -> List the available plugins.
pkg search -> Search for the given pattern in the remote package repositories.
pkg update -> Update the available remote repositories.
pkg upgrade -> Upgrade a package to a newer version.
pkg autoremove -> Remove unneeded dependencies.
pkg set -A 1 -> Change a package from non-automatic to automatic, which will make autoremove allow it be removed once nothing depends on it.
pkg audit -> Audit installed packages for security advisories.
pkg check -s -a -> Check installed packages for checksum mistakes.
pkg check -d -a -> Check for missing dependencies.

clear_history

#!/bin/sh
#
# This will override the terminal history file
#
echo '' > '/home/{username}/.bash_history'

clear_vim

#!/bin/sh
#
# This will override the VIM history file
#
echo '' > '/home/{username}/.viminfo'

Configuring static ip address

The new way for configuring your ethernet adapter

This has been tested with Arch Linux.
But should also work on every other GNU/Linux distro.

"ifconfig" is replaced by "ip addr"

For debian users...
Modifying /etc/network/interfaces is not necessary anymore.
Because this was typically for debian or debian based distros.

They changed this so that you only have remember the same commands
which works on every other GNU/Linux distro.

1)Giving a static ip address.

ip addr add <ipv4/prefix or ipv6/prefix> dev <interface>
Example: ip addr add 192.168.0.2/24 dev enp2s5

2)Add default gateway for your interface.

ip route add default via <ipv4> dev <interface>
Example: ip route add default via 192.168.0.1 dev enp2s5

No need to restart your ethernet adapter!!
Which is really nice.

So those are the two commands you need to learn.
And those will work for all GNU/Linux distributions.
This makes testing or using other GNU/Linux distros alot more
easier.

cpu_temp

Monitor the CPU temperature
---------------------------
To begin with you need lm-sensors package.
sudo apt-get install lm-sensors

Use following command to setup your sensors, if it's the first time.
sudo sensors-detect

The sensors-detect might not detect everything depending on your computer support.
You may still find a basic set of sensors for the CPU.

Real-time temperature display in the Terminal.
watch -n (delay in seconds) -d/-f sensors
ex.: watch -n 1 -d sensors

create-startup-script

Create a script that executes at startup (https://www.debian-administration.org/article/28/Making_scripts_run_at_boot_time_with_Debian)
----------------------------------------

1. Create your script in /etc/init.d and add:
  ### BEGIN INIT INFO
  # Provides:          skeleton
  # Required-Start:    $remote_fs $syslog
  # Required-Stop:     $remote_fs $syslog
  # Default-Start:     2 3 4 5
  # Default-Stop:      0 1 6
  # Short-Description: Example initscript
  # Description:       This file should be used to construct scripts to be
  #                    placed in /etc/init.d.
  ### END INIT INFO

Otherwise you will get "insserv: warning: script '{script}' missing LSB tags and overrides" when adding in "update-rc.d".
You can change the start and stop order of your script.

2. chmod 755 /etc/init.d/{script}
3. update-rc.d {script} defaults

Done!

To remove your script:
update-rc.d -f {script} remove

gentoo-install

https://wiki.gentoo.org/wiki/Handbook:X86/Full/Installation

Partitioning
-------------
parted -a optimal /dev/sdb
mklabel gpt
mkpart primary 1MiB 3MiB (bios)
name 1 grub
set 1 bios_grub on
mkpart primary ext4 3MiB 131MiB (boot)
name 2 boot
set 2 boot on
mkpart primary 130MiB 643MiB
name 3 swap
mkpart primary ext4 643MiB 100%
name 4 rootfs

Creating file systems
----------------------
# ext4 partitions smaller than 8Gb
mke2fs -j -T small /dev/sdb

mkfs.ext4 /dev/sdb2
mkfs.ext4 /dev/sdb4
mkswap /dev/sdb3
swapon /dev/sdb3

Mounting
---------
mount /dev/sdb4 /mnt/gentoo
mkdir /mnt/gentoo/boot
mount /dev/sdb2 /mnt/gentoo/boot

Installing a stage tarball
---------------------------
date -R

# if date is not right
date MMDDhhmmYYYY

cd /mnt/gentoo
links https://www.gentoo.org/downloads/mirrors/

# download stage3-<arch>-<release>.tar.bz2
# checksums stage3-<arch>-<release>.tar.bz2.DIGESTS.bz2

openssl dgst -r -sha512 stage3-<arch>-<release>.tar.bz2
openssl dgst -r -whirlpool stage3-<arch>-<release>.tar.bz2

# check both hashes with those from DIGESTS
cat stage3-<arch>-<release>.tar.bz2.DIGESTS.bz2

tar xvjpf stage3-*.tar.bz2 --xattrs

Configuring compile options
----------------------------
vim /mnt/gentoo/etc/portage/make.conf

# commented listing of all possible variables
:tabnew /mnt/gentoo/usr/share/portage/config/make.conf.example

CFLAGS="-march=native -O2 -pipe"
MAKEOPTS="-j<CPU cores + 1>"

# add extra modules in USE
USE = "pulseaudio python networkmanager lm_sensors"

VIDEO_CARDS=""
INPUT_DEVICES=""
ALSA_CARDS=""

:wq

Chrooting
----------
mirrorselect -i -o >> /mnt/gentoo/etc/portage/make.conf
mirrorselect -i -r -o >> /mnt/gentoo/etc/portage/make.conf

# double check if the mirrors are selected
cat /mnt/gentoo/etc/portage/make.conf

cp -L /etc/resolv.conf /mnt/gentoo/etc/
mount -t proc proc /mnt/gentoo/proc
mount --rbind /sys /mnt/gentoo/sys
mount --make-rslave /mnt/gentoo/sys
mount --rbind /dev /mnt/gentoo/dev
mount --make-rslave /mnt/gentoo/dev
chroot /mnt/gentoo /bin/bash
source /etc/profile
export PS1="(chroot) $PS1"

Configuring Portage
--------------------
emerge-webrsync
emerge --sync
eselect profile list
eselect profile set 3

Timezone
---------
echo "Europe/Brussels" > /etc/timezone
emerge --config sys-libs/timezone-data

Configure locals
-----------------
nano -w /etc/locale.gen
locale-gen
eselect locale list
eselect locale set 2 (en_US.utf8)
env-update && source /etc/profile

Installing the sources
-----------------------
emerge -av sys-kernel/gentoo-sources

Default:Manual configuration
-----------------------------
emerge -av sys-apps/pciutils
lsmod (kernel modules the live cd uses)
cd /usr/src/linux
make menuconfig (really important configs, know what you are doing)
make && make modules_install
make install

Using genkernel
----------------
ermerge -av sys-kernel/genkernel
nano -w /etc/fstab

>> /dev/sda2	/boot	ext4	defaults	0 2

genkernel all

Kernel modules
---------------
# view all available modules
find /lib/modules/<kernel version>/ -type f -iname '*.o' -or -iname '*.ko' | less
nano -w /etc/conf.d/modules

emerge -av sys-kernel/linux-firmware

Network information
--------------------
nano -w /etc/conf.d/hostname
emerge -av --noreplace net-misc/netifrc
nano -w /etc/conf.d/net

# if DHCP
>> config_<iface>="dhcp"

# static
>> config_<iface>="192.168.x.x netmask 255.255.255.0 brd 192.168.x.255"
	routes_<iface>="default via 192.168.x.1"

cd /etc/init.d
ln -s net.lo net.<iface>
rc-update add net.<iface> default
emerge -av sys-apps/pcmciautils

System information
-------------------
passwd
nano -w /etc/rc.conf
nano -w /etc/conf.d/keymaps
nano -w /etc/conf.d/hwclock

# none UTC
>> clock="local"

System logger
--------------
emerge -av app-admin/syslog-ng
rc-update add syslog-ng default
emerge -av sys-process/cronie
rc-update add cronie default
emerge -av sys-apps/mlocate

Networking tools
-----------------
emerge -av net-misc/dhcpcd

Default: Using GRUB2
---------------------
# using BIOS
emerge -av sys-boot/grub
grub2-install /dev/sdb

# using UEFI
echo GRUB_PLATFORMS="efi-64" >> /etc/portage/make.conf
emerge -av sys-boot/grub
grub2-install --target=x86_64-efi --efi-directory=/boot

grub2-mkconfig -o /boot/grub/grub.cfg

Rebooting the system
---------------------
exit
umount -l /mnt/gentoo/dev{/shm,/pts,}
umount /mnt/gentoo{/boot,/sys,/proc,}
reboot

Disk cleanup
-------------
rm -v /stage3-*.tar.bz2*

Kill processes

How to kill a specific process in Linux.

You might already know, you can only kill processes by knowing their PID.
So first you need to find out what's the PID.

$ ps aux | grep <process_name> : POSIX and UNIX method
$ ps -ef | grep <process_name>

The output is a little bit different.

If you see only one reponse it means the process you are looking for is not running.
If there are more than one. Most of times it's the first result the one you are looking for.

After you have identified your process. Just kill it as root.

$ sudo kill -9 <PID>

-9 flag means HALT.

Mounting devices on Linux

Mount a USB drive on Linux:
Check for available devices to mount:
$ sudo fdisk -l

$ sudo mount -v '/dev/{device}{partition}' '/{mount dir}'

I recommend using '/mnt' as mount.
But you can also use '/media/{username}' which is what Ubuntu does.
If you want to mount multiple devices you should consider making directories.

$ sudo mkdir '/mnt/USB DISK'
$ sudo mount -v '/dev/sdc1' '/mnt/USB DISK'

Will mount but the -v (verbose) will argue because of the type.
You can give a type which is better but you don't need it.
It will choose the right one. But here an example:
$ sudo mount -v -t vfat '/dev/sdc1' '/mnt/USB DISK'

Now it won't argue anymore.

Unmount a USB drive on Linux:
First you need to check what you want to unmount.
You can do this with following command:
$ sudo mount -l

If you mount with the system or auto mounts.
You can go in the directory where the device is mounted.
There are 2 places '/mnt' or '/media' differs from distro.
In my case Linux Mint (Ubuntu based) it's '/media'.

More specific '/media/{username}/'
Be sure to check it with:
$ ls -al '/media/{username}' <- will show hidden files and folders.

How to unmout (examples):
$ sudo umount -v '/mnt/USB DISK'
$ sudo umount -v '/media/{username}/{device_name}'
$ sudo umount -v '/dev/sdc1'

Do not forget to remove the directory/directories you created.
$ sudo rmdir '/mnt/USB DISK' <- save remove. It will fail if it's not empty.

Incase you want to remove the directory and all files and all subdirectories.
$ sudo rm -rv '/mnt/USB DISK'
$ sudo rm -rfv '/mnt/USB DISK' <- -f is Force in case you got a problem

Yes, it's 'umount' not 'unmount'!
-v flag is verbose. Might give helpful hints if something went wrong.

Real life situation:
Laptop with SD card reader (sdb).
Only 1 device connected (USB pen drive device sdc)

$ sudo fdisk -l

Look for all sdc. Usually 2, 1 = /dev/sdc + 1 = /dev/sdc1.
If you have more than one partition you will have more '/dev/sdc2'

But I only have one partition so sdc1.
Will first make a directory for structure purpose.

$ sudo mkdir '/mnt/USB DISK'
$ sudo mount '/dev/sdc1' '/mnt/USB DISK'

To unmount you have the choice.
Unmount by partition location '/dev/sdc1' or mount point '/mnt/USB DISK'

You might prefer using the mount point IF you have some structure.

Interesting command:
$ sudo mount -l

It gives all mounted devices and their mount point.
> /dev/sdc1 on /mnt/USB DISK type vfat (rw) [USB]

$ sudo umount '/dev/sdc1'
$ sudo umount '/mnt/USB DISK'

And remove the directory you created. Which is annoying ofcourse.

$ sudo rmdir '/mnt/USB DISK'

-r = recursive (will remove everything in side the folder)
-v = verbose (gives extra information for debugging)

And if you don't use -r it won't remove the directory.
> rm: cannot remove ‘/mnt/USB DISK’: Is a directory

p2p_connection

Grant internet connection to a Raspberry Pi connected peer-to-peer with a computer
----------------------------------------------------------------------------------

Has been done with Ubuntu 12.04 LTS

Info about:
Peer-to-peer with Raspberry Pi:
https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=36596

Sharing a wireless connection via ethernet port:
http://chrisjrob.com/2011/03/14/sharing-a-wireless-connection-via-ethernet-port/

Mount the SD card into the PC:
mount /dev/mmcblk0p2 /mnt

Edit /mnt/ect/network/interfaces with following:
auto eth0
allow-hotplug eth0
iface eth0 inet static
address 10.42.0.3
netmask 255.255.255.0
gateway 10.42.0.1

Set a shared network for wired connection:
NetworkManager > Edit Connections...
Ethernet > Wired connection 1 - Edit...
IPv4 Settings > Methods: Shared to other computers - Save...

Interface eth0 should get 10.42.0.1 as IP address

Activate IP forwarding, and setup iptables to NAT:
sysctl -w net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

If the client gets Host Prohibited responses:
iptables -F FORWARD
iptables -A FORWARD -j ACCEPT
iptables -nvL

Boot Raspberry Pi, get console access and internet should work:
ssh pi@10.42.0.3
sudo apt-get update

Remove rules and chains:
iptables -F
iptables -X
iptables -t nat -F

rpm packages

How to install rpm packages on Debian and Ubuntu

Install alien and all the dependencies it needs:
apt-get install alien dpkg-dev debhelper build-essential

To convert a package from rpm to debian (.deb) format:
alien <package>.rpm

Finally, install your package!
dpkg -i <package>.deb

Source:
http://namhuy.net/1207/how-to-install-rpm-packages-on-ubuntu-mint-or-debian.html

Samba config

[global]
    workgroup = WORKGROUP
    dns proxy = no
    log file = /var/log/samba/log.%m
    max log size = 1000
    syslog = 0
    panic action = /usr/share/samba/panic-action %d
    server role = standalone server
    passdb backend = tdbsam
    obey pam restrictions = yes
    unix password sync = yes
    passwd program = /usr/bin/passwd %u
    passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
    pam password change = yes
    map to guest = bad user
    usershare allow guests = yes

[homes]
    comment = Home Directories
    browseable = no
    read only = yes
    create mask = 0700
    directory mask = 0700
    valid users = %S

[public]
    comment = Public Storage
    path = /mnt/shares/public
    create mask = 0775
    directory mask = 0775
    read only = no
    browseable = yes
    guest ok = yes
    writeable = yes
    available = yes
    public = yes
    force user = nobody

swap-partition-numbers

Swapping partition numbers
--------------------------
This method should let you rewrite the partition table
without losing any content on existing partitions.
I'm not responsible for any data loss during the process.

Example made using a USB thumb drive. (/dev/sdb with sdb1 and sdb2)

1. Create a directory for practical purpose
mkdir ~/partition-swap

2. Output the current partition table
sudo sfdisk -d /dev/sdb > sdb.old

3. Copy the partition table for future modifications
sudo cp sdb.old sdb.new

4. Modify the partition table
vim sdb.new

5. Rewrite the partition table
sudo sfdisk --no-reread -f /dev/sdb < sdb.new

vim-basics

VIM basics
------------------
Using tabs (https://www.linux.com/learn/tutorials/442422-vim-tips-using-tabs):
vim -p <file> <file> <file>
:tabnew <file>

:tabn <- next tab
:tabp <- previous tab

Using splitview (https://www.linux.com/learn/tutorials/442415-vim-tips-using-viewports):
:split <file>

Change file CTRL+w

Copy, cut and paste (http://vim.wikia.com/wiki/Copy,_cut_and_paste):
You can use the Visual mode with v.
Select your text by navigating with the arrows.

y=yank=copy
P=past before cursor
p=past after cursor
d=delete=cut

Searching words (http://vim.wikia.com/wiki/Searching):
Normal mode type:
/<your_word>

Forward searching by pressing *(asterisk)
Backward searching #(hash sign)

Good to know:
:w [<file>]<- save/save as
:q <- quit
:wq <- save and quit
:q! <- force quit, losing all changes if not saved
gg <- Top of the file
SHIFT+G <- Bottom of the file
u <- Undo
Ctrl+R <- Redo
:%!xxd <- Turns ViM into a Hex Editor
:%!xxd -r <- Turns ViM back to normal
:noh <- clear search highlight from hlsearch

xampp-installation_guide

Installation guide XAMPP
------------------------

1.Extract the downloaded file to "/opt":
# sudo tar xvfz xampp-linux-1.7.7.tar.gz -C /opt

2.To start XAMPP simply call this command:
# sudo /opt/lampp/lampp start

3.Test in your browser if it works:
> http://localhost

=============================
NOT NEEDED FOR DEVELOPMENT !!
=============================

Missing security in XAMPP
-------------------------

1.The MySQL administrator (root) has NO password.
2.The MySQL daemon is accessible via network.
3.ProFTPD uses the password "lampp" for user "nobody".
4.PhpMyAdmin is accessible via network.
5.Examples are accessible via network.
6.MySQL and Apache running under the same user (nobody).

To fix most of the security weaknesses:
# sudo /opt/lampp/lampp security