Linux

Process's states

R - TASK_RUNNING: The process is either executing on a CPU or waiting to run.
S - TAS K_I N T E R R U PT I BL E : The p rocess i s waiti n g for some c o n d i t i o n : a
h a rdware request, system resou rce a ccess, or s i g n a l . W h e n a n event o r
s i g n a l satisfies t h e c o n d i t i o n , the process ret u r n s to Running.

D - TAS K_U N I N T E R R U PT I B L E : This p rocess is a l s o Sleeping, but u n l i ke s state,
w i l l not res p o n d to d e l ivered s i g n a l s . Used o n l y u n d e r specific conditions i n
w h i c h p rocess i nterruption may cause a n u n p re d i ct a b l e d evice state.

K - TAS K_K I L L A B L E : I d e n t i c a l to the u n i nterrupt i b l e D state, but modified to
a l l ow the w a i t i n g t a s k to res pond to a s i g n a l to be k i l l e d (exited c o m p l etely).
U t i l i t ies f re q u e n t l y d i s p l a y Killable p rocesses a s D state.

T - TAS K_STO P P E D : T h e p rocess h a s been Stopped (s u s p e n ded), u s u a l l y by
b e i n g s i g n a led by a user or an other process. The process can be continued
(resumed) by an others ignal to return to Running.

T - TASK_TRACED: A process that is being debugged is also temporarily
Stopped and shares the same T state flag.

Z - EXIT_ZOMBIE: A child process signals its parent as it exits. All resources
except for the process identity (PlD) a re released.

X - EXIT_DEAD: When the parent cleans up (reaps) the remaining child process
structure, the process is now released completely. This state will never be
observed in process - listing utilities.

iptables

sudo iptables -t nat -A PREROUTING --dst 192.168.100.101 -p tcp --dport 1900 -j DNAT --to-destination 10.0.0.2:1880 server:1900 -> vm:1880

mail

MTA - передача писем, только SMTP
MDA - получение писем, MDA общается с MTA для их получения

MTA - exim, postfix, sendmail
MDA - dovecot, cyrus

nextcloud preview configuration

I don't want to generate all the preview sizes


This is possible since version 1.0.8. Just set the correct values via the command line 
``` ./occ config:app:set --value="32 64 1024" previewgenerator squareSizes ./occ config:app:set --value="64 128 1024" previewgenerator widthSizes ./occ config:app:set --value="64 256 1024" previewgenerator heightSizes ``` 
This will only generate:

• square previews ofL 32x32, 64x64 and 1024x1024* aspect ratio previews with a width of: 64, 128 and 1024
• aspect ratio previews with a height of: 64, 256 and 1024


Note:

• preview sizes are always a power of 2.
• The smallest size is 32
• The max size is determined by your preview settings in config.php

Some stuff

disown -a && exit - выйти не закрывая работающие процессы

VirtualBox

VBoxManage clonehd absolutepath/image.vdi image.img --format raw - сконвертировать vdi в сырой диск