Sviat

Install docker & k8s

2020-11-24T08:55:28.610Z

sudo su
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
echo "deb http://apt.kubernetes.io kubernetes-xenial main" >> /etc/apt/sources.list.d/kubernetes.list
add-apt-repository "deb https://download.docker.com/linux/$(. /etc/os-release; echo "$ID") $(lsb_release -cs) stable"
apt-get update
apt-get install -y docker-ce kubelet kubeadm kubectl
swapoff -a
sed -i '/ swap / s/^/#/' /etc/fstab

Bash tips

2020-10-20T13:04:11.444Z

General

kill procces by port

sudo kill $(sudo lsof -ti:port)

create symlink
`ln -sf /path/to/file /path/to/symlink`

open url from bash

xdg-open http://google.com

bash loop

for (;;); do command; command-2; done

output timestamps

ts # timestamp
ts -i # each output duration
ts -s # time taken from start

find & replace in all files in folder & subfolders

sudo kill $(sudo lsof -ti:port)
ack -l 'pattern' | xargs perl -pi -E 's/pattern/replacement/g'

visualize git repo development

gource --stop-at-end --hide filenames,usernames,dirnames -1920x1080 -s 0.5 -o - | ffmpeg -y -r 30 -f image2pipe -vcodec ppm -i - -vcodec libx264 -preset ultrafast -pix_fmt yuv420p -threads 0 -bf 0 gource.mp4 -crf 0

list opened ports and its process names

netstat -nlpt

postgres

install psql

sudo apt install postgresql postgresql-contrib

drop connections for dbname

SELECT pg_terminate_backend(pg_stat_activity.pid) FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'dbname' AND pid <> pg_backend_pid();

create full duplicate of dbname named dbname_copy with db_user owner

create database dbname_copy WITH TEMPLATE dbname OWNER owner;

check postgres certificates

curl https://raw.githubusercontent.com/thusoy/postgres-mitm/master/postgres_get_server_cert.py | python3 - host:port | openssl x509 -noout -dates

Aync execution for bash

2020-09-11T08:12:07.626Z

Easy way to manage scripts in the background

# in order to use in bash scripts add "set -m" to enable job control

echo > job-status
command1 || echo false > job-status &
command2 || echo false > job-status &
# repeat as much as needed
while [[ $(jobs) ]]; do fg; done
[[ $(cat job-status) != "false" ]]

Resize partition on running Linux instance

2020-08-18T09:17:00.439Z

Step 1: Add storage

As an example, we'll pick AWS and will add 5GB(60->65 GB).

Used space

Step 2: Resize physical partition

Use lsblk | grep -v loop to list all available disks and partitions

sudo growpart /dev/{device_label} {index} to resize partition

Step 3: Tell the system to use newly available space

sudo resize2fs /dev/{partition_label}

df -h / to check results