Jay jay-lannister

## 0_reuse_code.js
// Use Gists to store code you would like to remember later on
console.log(window); // log the "window" object to the console

## active-threads-of-a-jvm-process.sh
ps huH p <PID_OF_U_PROCESS> | wc -l


# nlwp = number of lightweight process
ps -o nlwp <PID_OF_U_PROCESS>

## expand-partition-on-aws-linux.sh
# references
# [Resizing Root Partition on Linux in Amazon EC2](https://linuxacademy.com/blog/linux/resizing-root-partition-on-linux-in-amazon-ec2/)

# 1. create a snapshot of the old hdd
# 2. create a new volume which has a more storage than the old one from the snapshot
# 3. check the new partition name you want to expand by running
lsblk

# 4. expand the hdd on the fly
resize2fs /dev/xvde

## 0_reuse_code.js
// Use Gists to store code you would like to remember later on
console.log(window); // log the "window" object to the console

## Asset.sql
select @@datadir;

## find.sh
# 문자열 "mysql"이 포함된 파일을 폴더 두 군데를 뒤져서 찾는다.
#
# /System/Library/LaunchDaemons/
# /Library/LaunchDaemons/

grep mysql {,/System}/Library/LaunchDaemons/*

## Show which processes are listening to which ports.sh
lsof -i | grep LISTEN

## kill.sh
# http://www.howtogeek.com/howto/ubuntu/kill-a-process-by-process-name-from-ubuntu-command-line/

# http://stackoverflow.com/questions/8594653/killing-all-process-from-command-line
#
# Side note -
#
# kill -9 is overkill (no pun intended) because it prevents the killed process from running cleanup (e.g., atexit() calls, like the difference between exit and _exit). It may or may not be a problem with firefox, but in general consider trying "kill -9" only after plain "kill" fails.


# kill

## attach-new-hdd.sh
fdisk -l

# CentOS 6 uses ext4 as a default filesystem
mkfs.ext4 /dev/xvdj

# CentOS 7 uses xfs as a default filesystem
mkfs.xfs /dev/xvdj


vim /etc/fstab

## prevent-too-many-connections-from-a-single-host.sh
# Reference: http://security.stackexchange.com/questions/42618/how-to-protect-tomcat-7-against-slowloris-attack


# Use firewall rules to prevent too many connections from a single host. This will mitigate run-of-the-mill Denial of Service attacks but not distributed ones (DDoS).

# Here is an example of an iptables command which can be used to limit the number of concurrent connections that can be established to port 80 from a single client host:

iptables -A INPUT -p tcp --syn --dport 80 -m connlimit --connlimit-above 50 -j REJECT

# This would, however, have side-effects if many users were legitimately connecting from a single IP (e.g. mega-proxy), so the number of connections would need to be tuned reasonably - dependant on the traffic expected.
	// Use Gists to store code you would like to remember later on
	console.log(window); // log the "window" object to the console
	ps huH p <PID_OF_U_PROCESS> \| wc -l


	# nlwp = number of lightweight process
	ps -o nlwp <PID_OF_U_PROCESS>
	# references
	# [Resizing Root Partition on Linux in Amazon EC2](https://linuxacademy.com/blog/linux/resizing-root-partition-on-linux-in-amazon-ec2/)

	# 1. create a snapshot of the old hdd
	# 2. create a new volume which has a more storage than the old one from the snapshot
	# 3. check the new partition name you want to expand by running
	lsblk

	# 4. expand the hdd on the fly
	resize2fs /dev/xvde
	# 문자열 "mysql"이 포함된 파일을 폴더 두 군데를 뒤져서 찾는다.
	#
	# /System/Library/LaunchDaemons/
	# /Library/LaunchDaemons/

	grep mysql {,/System}/Library/LaunchDaemons/*
	# http://www.howtogeek.com/howto/ubuntu/kill-a-process-by-process-name-from-ubuntu-command-line/

	# http://stackoverflow.com/questions/8594653/killing-all-process-from-command-line
	#
	# Side note -
	#
	# kill -9 is overkill (no pun intended) because it prevents the killed process from running cleanup (e.g., atexit() calls, like the difference between exit and _exit). It may or may not be a problem with firefox, but in general consider trying "kill -9" only after plain "kill" fails.


	# kill
	fdisk -l

	# CentOS 6 uses ext4 as a default filesystem
	mkfs.ext4 /dev/xvdj

	# CentOS 7 uses xfs as a default filesystem
	mkfs.xfs /dev/xvdj


	vim /etc/fstab
	# Reference: http://security.stackexchange.com/questions/42618/how-to-protect-tomcat-7-against-slowloris-attack


	# Use firewall rules to prevent too many connections from a single host. This will mitigate run-of-the-mill Denial of Service attacks but not distributed ones (DDoS).

	# Here is an example of an iptables command which can be used to limit the number of concurrent connections that can be established to port 80 from a single client host:

	iptables -A INPUT -p tcp --syn --dport 80 -m connlimit --connlimit-above 50 -j REJECT

	# This would, however, have side-effects if many users were legitimately connecting from a single IP (e.g. mega-proxy), so the number of connections would need to be tuned reasonably - dependant on the traffic expected.