I gathered some linux commands that i use a lot and consider useful.

sys_cheatsheet.md

Useful Commands Cheatsheet

Processes

Interactive Process Viewers

• top
• htop
• atop

List all processes in tree format

• ps -e -AH --forest -F

List processes in a tree format

Also show their arguments and pids

• pstree -plUa

List by memory consumption

• ps aux --sort pmem

Search process by command

• ps -f -C script.rb

Search for a process by name

• pgrep -l some_process

Trace a process

• strace -f -p $PID

Which files are open by a process

• lsof -p $PID

Killing Processes

Kill by name

• pkill postgres

Packages

update installed packages

• sudo apt-get update && apt-get update -y

search for installed package by name

• dpkg-query -l | grep -i postgres

find where an installed package is located

• dpkg -L <packagename>

Network

Which process is listening on which port

• netstat -tlpu

Tcp sockets in use

• lsof -nPi tcp

Lookup some domain's mx records

• dig zorbash.com mx

Drop requests from a specific ip

• iptables -I INPUT -s 66.75.84.220 -j DROP

Memory

Basic Info

• free -m

Detailed Info

• cat /proc/meminfo

Disk

Reads/Writes per disk

• iostat -xnk 5

Deployments

Copying the public key to the remote server(s)

• ssh-copy-id remote-server.org

Databases

Postgres

Create db

createdb mydb --owner your_highness

Create psql user

createuser -s your_highness #creates a superuser with username your_highness

Install postgis extension

psql -d yourdatabase -f postgis.sql

psql -d yourdatabase -f postgis_comments.sql

psql -d yourdatabase -f spatial_ref_sys.sql

Extra Resources

rubytune