Linux: Prepare

Adapt old .bashrc to latest distro /etc/skel/.bashrc

sudo update-alternatives --list editor
sudo update-alternatives --config editor

In file: ~/.profile

• umask 002 (default), RW for user, RW for group and R for others - create dirs as 775 and files as 664
• umask 022 (default for root), 755 and 644
• umask 077 only RW for user, not other access
• umask 007 RW for user, RW for group

NOTE!: Problem appears with non default user umask and sudo command usage. After sudo umask is still set to the user umask, which is correct. But can lead to some unpredicted behavior i.e. installing system-wide packages - new file will be created with incorrect umasks (user umask).

To prevent this:

/etc/sudoers

Defaults        umask_override
Defaults        umask=0022

dpkg --add-architecture i386
apt-get update
apt-get install gpm tcpdump bmon tinc ppp pptpd mc links2 gparted hdparm smartmontools smart-notifier valgrind openssh-server
apt-get install wireshark mtr

1. Disable systemd time service: systemctl disable –now systemd-timesyncd
2. Install ntpdate and ntp
3. Edit /etc/default/ntp and add -g argument.
4. Switch RTC to UTC time:

timedatectl set-local-rtc 0
ntpd -gxn
hwclock --systohc

echo "blacklist pcspkr" > /etc/modprobe.d/nobeep.conf

apt-get install resolvconf

Add own nameserver into /etc/resolvconf/resolv.conf.d/base

nameserver 8.8.8.8

and execute

sudo resolvconf -u

dpkg-reconfigure keyboard-configuration
apt-get install console-data
dpkg-reconfigure console-data
dpkg-reconfigure locales

add

• pl_PL
• pl_PL.UTF-8

In Debian, locales are handled in /etc/default/locale. File /etc/environment is deprecated.

grep pam_env.so /etc/pam.d/*
...
/etc/pam.d/login:session       required   pam_env.so readenv=1
/etc/pam.d/login:session       required   pam_env.so readenv=1 envfile=/etc/default/locale
...

Remember to set paper_format

/etc/udev/rules.d/60-schedulers.rules

#ACTION=="add|change", KERNEL=="sd*[!0-9]|sr*", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="cfq"
ACTION=="add|change", KERNEL=="sd*[!0-9]|sr*", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="bfq"
# ACTION=="add|change", KERNEL=="sd*[!0-9]|sr*|mmcblk[0-9]*", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="deadline"  
ACTION=="add|change", KERNEL=="sd*[!0-9]|sr*|mmcblk[0-9]*", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="kyber"
ACTION=="add|change", KERNEL=="nvme[0-9]n[0-9]*", ATTR{queue/scheduler}="kyber"

cat /sys/block/sd*/queue/scheduler

There are 2 queues, one for read & one for write operations.

• none is just a First In First Out standard queue of I/O operations (it still merges some requests).
• cfq (Completely Fair Scheduling) is similar to the Round Robin algorithm and basically allots a fixed execution time for each I/O operation (they are implemented as a circular queue)
• deadline is like a priority queue with an aging concept. Basically it adds a deadline for each I/O operation & implements a priority queue

Supported in kernel >=4.12. It is disabled by default. To use multi-queue schedulers compile kernel with CONFIG_SCSI_MQ_DEFAULT=y or pass parameter scsi_mod.use_blk_mq=1 in boot loader.

Linux Multi-Queue Block IO Queueing Mechanism

/etc/udev/rules.d/60-schedulers.rules

ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="bfq"
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="mq-deadline"

sudo udevadm control --reload
sudo udevadm trigger
cat /sys/block/sd*/queue/scheduler

To disable console annoying beep: * System wide by removing PC Speaker module:

rmmod pcspkr
sudo echo "blacklist pcspkr" > /etc/modprobe.d/pcspkr-blacklist.conf

sudo apt-get install wireshark cups

sudo usermod -G lp,lpadmin,dialout,sudo,audio,video,netdev,vboxusers,wireshark,kismet,i2c user_login

sudo apt-get install pigz pbzip2 pxz lbzip2

To force using parallel packers system-wide:

ln -s /usr/bin/lbzip2 /usr/local/bin/bzip2
ln -s /usr/bin/lbzip2 /usr/local/bin/bunzip2
ln -s /usr/bin/lbzip2 /usr/local/bin/bzcat
ln -s /usr/bin/pigz /usr/local/bin/gzip
ln -s /usr/bin/pigz /usr/local/bin/gunzip
ln -s /usr/bin/pigz /usr/local/bin/zcat
ln -s /usr/bin/pixz /usr/local/bin/xz

or use bash aliases:

.bashrc

alias gzip='pigz'
alias gunziip='unpigz'
alias bzip2='pbzip2'
alias bunzip2='pbunzip2'
alias xz='pxz'

some benchmarks (i7-3770K), BTRFS FS +NoCOW attrib

apt-get install git 
git config --global user.name "my name"
git config --global user.email myemail@address.pl
apt-get install git-cola etckeeper kdiff3

Disable mandb updates after apt:

echo "set man-db/auto-update false" | debconf-communicate; dpkg-reconfigure man-db