***************
* Linux stuff *
***************


---------------
| chmod table |
---------------

value	read	write	execute
0	no	no	no
1	no	no	yes
2	no	yes	no
3	no	yes	yes
4	yes	no	no
5	yes	no	yes
6	yes	yes	no
7	yes	yes	yes


** practical **
---------------
Find [string] from unknown file:
	find . -name "*.*" | xargs -L1 grep -H [string]

Find [file], but don't print errors:
	find -name [file] 2>/dev/null

Run graphical [program] on (f.e. remote) machines own display:
	DISPLAY=:0 [program]


** System  **
-------------
Set swappiness (default 60):
	echo [0-100] > /proc/sys/vm/swappiness

Remove CLI beeps:
	nano -w /etc/inputrc
and set:
	set bell-style none


** rescue **
------------
Simplify HDD settings (useful to perform before trying to rescue data):
	hdparm -A0 -B255 -c0 -d0 -n0 -M128 -r1 -W0 /dev/sdx

Try to rescue what is left on HDD (target could be f.e. sda6):
	myrescue -b1024 -B bitmap -S -r1 /dev/[source] /dev/[target]
Ps. Check also ddrescue.



*******************
* Debian specific *
*******************


** dpkg **
----------
Get status of package:
	dpkg --get-selections [package]

Set [package] on hold:
	echo "[package] hold" | dpkg --set-selections

Show which packages are on hold:
	cat /var/lib/dpkg/status | grep -B1 Status | grep -B1 hold

List contents of deb file:
	dpkg -c [package.deb]

List all the files installed by [package]:
	dpkg -L [package]


** APT **
---------
Install from specified repository (-t flag):
	apt-get -t [repository] install [package]

Location of packages stored (cached) by apt:
	/var/cache/apt/archives/

Cleaning (removing) all stored packages from cache:
	apt-get clean

Cleaning (removing) not currently installed packages from cache:
	apt-get autoclean

Package extended states (auto-installed or manually installed) are stored in:
	/var/lib/apt/extended_states