You could also do

chown -R username:groupname .

, which would change the permissions on the current directory, and then recurse down inside of it and all subfolders to change the permissions.

chmod -R 666 /var/www

will give read, write permissions for everyone.

Partitions:

lsblk -f 

or:

# file -sL /dev/sd*

result:

/dev/sda1: Linux rev 1.0 ext4 filesystem data, UUID=63fa0104-4aab-4dc8-a50d-e2c1bf0fb188 (extents) (large files) (huge files)
/dev/sdb1: Linux rev 1.0 ext2 filesystem data, UUID=b3c82023-78e1-4ad4-b6e0-62355b272166
/dev/sdb2: Linux/i386 swap file (new style), version 1 (4K pages), size 4194303 pages, no label, UUID=3f64308c-19db-4da5-a9a0-db4d7defb80f

Check ext2 ,ext3, ext4 partition:

sudo umount /dev/sdXN
sudo e2fsck -f -n /dev/sdXN

-n reports issues without making changes. If you want e2fsck to repair errors interactively, rerun without -n:

sudo e2fsck -f /dev/sdXN

Pack:

tar czf name_of_archive_file.tar.gz name_of_directory_to_tar

Unpack:

tar -xzvf file.tar.gz

SCP:

scp [OPTION] [user@]SRC_HOST:]file1 [user@]DEST_HOST:]file2

Rsync to NTFS filesystem (rsync have to be installed on boths machines)

rsync -rtv --modify-window=1 [user@]SRC_HOST:]file1 [user@]DEST_HOST:]file2

Password less SSH http://www.linuxproblem.org/art_9.html

cat .ssh/id_ed25519.pub | ssh b@B 'cat >> .ssh/authorized_keys'

Scan network:

sudo nmap -sn 192.168.0.0/24

https://reintech.io/blog/setting-up-nfs-server-on-debian-12

Add PPA Debian:

sudo apt -y install software-properties-common python3-launchpadlib

Hex Editors for Linux

sudo apt install hexedit