Ivan Pan ipan

find out what process is binding the port 4000 with lsof

lsof -i tcp:4000

and use netstat

netstat -lnt -p tcp

do not check host key

ssh -o StrictHostKeyChecking=no user@ssh-server

.ssh/config settings for all hosts with DSA

PubkeyAcceptedKeyTypes=+ssh-dss
KexAlgorithms +diffie-hellman-group1-sha1

https://www.mostlynetworks.com/2016/10/fixing-macos-sierraopenssh-7-x-compatibility/

Using sed to append something after search pattern.

sed -i '/PATTERN/a\APPENDED' <file>

For example, this will add "sample": "sample x", after "flows": .*, to test_inactive.json

sed -i '/"flows": .*,/a\ "sample": "sample x",' test.json

Example config for mac only

Host bastion
  Hostname ssh-bastion.example.com
  IdentityFile ~/.ssh/bastion_ssh.key
  User bastion-user

# internal server on private network
Host 172.18.* 192.168.*

ProxyJump bastion

Accepting licenses

sudo xcodebuild -license accept

Both include flags needs to go before exclude. The -z, --compress will compress the files during transfer and the -m, --prune-empty-dirs will delete empty folders in destination.

rsync -avmz --include="*/" --include="*.sh" --exclude="*" "$from" "$to"

https://stackoverflow.com/questions/11111562/rsync-copy-over-only-certain-types-of-files-using-include-option/11111793

	$ nproc
	32


	$ lscpu
	Architecture: x86_64
	CPU op-mode(s): 32-bit, 64-bit
	Byte Order: Little Endian
	CPU(s): 32
	On-line CPU(s) list: 0-31

	# jq can not write back to the same file
	for i in `find . -name '*.json'`
	do
	jq '.' $i > $i.tmp
	mv $i.tmp $i
	done

	# oneliner version
	# for i in `find . -name '*.json'`; do jq '.' $i > $i.tmp && mv $i.tmp $i; done

	# only add when the json file does not have new line
	git ls-files \| grep json \| while read f; do tail -n1 $f \| read -r _ \|\| echo >> $f; done

	# https://unix.stackexchange.com/questions/31947/how-to-add-a-newline-to-the-end-of-a-file
	# https://unix.stackexchange.com/questions/192786/what-is-the-meaning-of-read-r

	"""
	For Python ≥ 3.2, os.makedirs has an optional third argument exist_ok that, when true, enables the mkdir -p functionality -- unless mode is provided and the existing directory has different permissions than the intended ones; in that case, OSError is raised as previously.
	"""

	import errno
	import os

	def mkdir_p(path):
	try:
	os.makedirs(path)