Useful in Linux

When local DNS is not resolved in laptop/PC (Ubuntu)

sudo ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf

What DNS on my wlan connection?

nmcli dev show wlp2s0 | grep -i dns

bash

modify bash

sudo nano ~/.bashrc

reload bash

source ~/.bashrc

Flush DNS Cache Linux

client

sudo /etc/init.d/nscd restart

bind9

rndc flush

Delete all files with certain extension

find . -type f ! -name "*.pdf" -exec rm -rf {} \;

PHP Packages

search available packages

sudo apt-cache search php7-* 

install certain package

sudo apt-get install php7.0-xxxxxx

install PHP on Ubuntu

link

Restart sound card

sudo alsa reload

Make a symlink

ln -s TARGET_FOLDER SYMLINK_FOLDER

FSTAB related

uid's disks

sudo blkid

uid per device

ls -l /dev/disk/by-uuid

reload all mounts from fstab

sudo mount -a

Select other JAVA SDK version

sudo update-alternatives --config java 

Restart GUI in Linux Mint

Press ALT-F2
Press r
Press Enter key

Withold package from updating

sudo apt-mark hold package_name