.cheat-sheet

# correct time to specific zone:
timedatectl set-ntp true

# entering time manually:
timedatectl set-time "2019-12-31 18:17:16"

# pacman
pacman -Q     # list all installed packages
pacman -Qq    # list all installed packages without version number (quiet)
pacman -Qe    # list all explicitly installed packages
pacman -Qdt   # list all orphaned packages
pacman -Qn    # list packages installed from main repository
pacman -Qm    # list packages installed from AUR
pacman -Qo <file>   # get package owning provided file
pacman -Ql <package> # get files provided by the package
pacman -Qs    # search local repository for packages
pacman -R     # remove package
pacman -Rs    # remove package and it's dependencies
pacman -Rns   # remove package with it's dependencies and system config files
pacman -Sc    # clear cache of old packages

# If yaourt fails on verifying a source...
gpg --recv-keys <key>

# get default gateway
ip route

# list all open ports in given network
nmap 192.168.1.1/24

# list cached arp from kernel
ip neighbor

# list IP addreses, mac addresses and names of all devices in the network
sudo arp-scan -l

# get an IP assigned to an active interface
ifconfig $(ifconfig | grep RUNNING | grep -v LOOPBACK | awk -F: '{ print $1 }') | grep "inet " | awk '{print $2 }'

# resize tmp partition on the fly
sudo mount -o remount,size=10G tmpfs /tmp

# output only a part of searched term with grep
echo "Main PID: 535 (master)" | grep -oP '(?<=(PID):\s)[0-9]+'

# unpack .deb package
ar -vx package.deb && tar xvf data.tar.gz -C /target/directory

# replace only part of match in sed
echo "some code: MKTAG('m' ,  'p', '4',  'a'); return;" | sed -E "s|MKTAG\('([A-z0-9])'[, ]*'([A-z0-9])'[, ]*'([A-z0-9])'[, ]*'([A-z0-9])'\)|mp4tag(\"\1\2\3\4\")|g"

# coredumps location (arch linux)
/var/lib/systemd/coredump/

# get sum of number of lines of files in a directory
count=0; for f in $(find . -name '*.c' -o -name '*.cc' -o -name '*.h'); do ((count+=$(wc -l < $f))); done; echo $count

# addr2line - get source file line corresponding to an address in a binary
addr2line -e file.bin -a +0x4c37e

# use vim as a command line file editor
vim FILENAME -i NONE -u NORC -U NONE -nNes "+/tscpd.conf" "+norm dd" "+norm gg" "+norm P" "+wq"

# mount drive with write permissions for everyone
sudo mount /dev/sdb2 /mnt/ -o umask=000