SYSTEM MANAGEMENT v1

Image source: Willi Glenz - SYSTEM MANAGEMENT

# journalctl -b 0

atop dstat free glances htop info inxi kill man pinfo ps pwd top tuptime uptimeusers vmstat w whoami 
cd ls man mv cp open less
bg fg jobs ctrl-z 

veracrypt.fr/en/Documentation.html 
sectools.org 
kernel.org 

/var/log

# apt-get update && apt-get upgrade && apt-get dist-upgrade
$ cat /etc/shells
# vim /etc/sudoers
# visudo
$ gnome-<tab><tab>
$ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head
# init 0
# ls<tab><tab>
$ pwgen -s 12
# rpi-update
# rkhunter --check --sk
# service netatop start && atop
# shutdown -r now
# shutdown -c
# shutdown -h 1:00
$ sudo !!
$ sudo su
# tripwire --init
$ uname -v
$ unset HISTFILE
# update-alternatives --config editor
$ PI=$(echo "scale=10; 4*a(1)" | bc -l)
$ apt-cache show vlc | less
# apt-get install kismet
$ cat /etc/fstab | grep -i swap
# cat /var/log/messages | awk '{print substr($0,0,12)}' | uniq -c | sort -nr | awk '{printf("\n%s ",$0) ; for (i = 0; i<$1 ; i++) {printf("*")};}' | less
$ df -hT
$ efibootmgr
$ find ~ -maxdepth 1 -type f -mtime 3
$ find ~ -maxdepth 1 -type f -exec grep "^alias " '{}' \; -print$ lastlog | less
$ find /etc -type f -print 2> /dev/null | less
$ find /etc/*tab -type f -print
$ free -h
$ inxi -v7
$ lastlog | less
$ lsblk
$ lsb_release -a
$ ps hax -o user | sort | uniq -c
$ script sessionlog_2018-10-30
$ set | less
# service cron status
# swapon -s
$ tuptime
$ vmstat 2 10
$ watch -n 5 free -m
$ whowatch
$ xload -update 1 -nolabel &

KERNEL
$ lsmod | wc -l
# journalctl -b 0

LOGGING
# tail -f /var/log/messages
# tail -fvn 25 /var/log/messages
# less +F /var/log/messages
# dmesg --facility=kern -H
# dmesg --level=err,warn -T
# journalctl -b 0

MULTIMEDIA
$ mpg123 -zvC /home/user/music/*
$ youtube-dl -F https://youtu.be/xyz
$ youtube-dl -f 22 https://youtu.be/xyz

SWAPPING
//
// $ free -h
// $ top
// $ vmstat -w
// $ cat /proc/swaps
// # fdisk -l
//
// # swapon -s
// # ls -lh /tmp 
// # dd if=/dev/zero of=/tmp/swap_tmp bs=1024 count=1000000
// # ls -lh /tmp
// # chmod 600 /tmp/swap_tmp
// # mkswap /tmp/swap_tmp
// # swapon /tmp/swap_tmp
// # swapon -s
//
// # blkid
// # vim /etc/fstab
// # Emergency swap partition
// UUID= (value from blkid)     none     swap     sw    0     0

TIME
# vim /etc/crontab
$ ls -l /etc/cron* | less

TROUBLESHOOTING
$ dstat -f 60 24
# testdisk
# grub-mkconfig -o /boot/grub/grub.cfg
# service netatop start && atop