Unix

August 19,2024

last update: 2024-11-19

If you are on a unix-like environment, ports < 1024 (like 80) will require superuser privileges.

Disk mounting and unmounting

sudo mount -o discard,defaults <diskid> <dir>

you can get the disk id by

ls -l /dev/disk/by-id

Checking disk usage

df

size of sum of files in directory

du -bch <dirname>

Checking the OS

lsb_release -a

or

cat etc/os-release

Sudo issues

When using aws a lot of times its annoying to type sudo for all commands. instead it is much simpler to just grant super user privileges to the ubuntu user only.

in the ubuntu shell do the following

sudo su -

this should switch to a different type of shell. Now, you are in the root user shell.

from there, run

passwd ubuntu

This should prompt you to set a new username password This is just icing on the cake for future use. As, I still am unable to find the default password.

Then, run

usermod -aG sudo ubuntu

This provides super user privileges to ubuntu.

Linux Screen

I’ve run too many processes on a screen

list screen

screen -ls

connect to screen

screen -r <id>

remove screen

screen -S <id> -X quit 

Scroll, ctrl+A then esc and scroll

detach, ctrl+A,D