Cheat Sheet

Linux

How to find which process is using a port?

netstat -nlp | grep 9090

How to generate a secure ssh key?

ssh-keygen -t ed25519 -C "$(whoami)@$(uname -n)-$(date -I)"

https://wiki.archlinux.org/title/SSH_keys

How to generate a random token or password?

openssl rand -hex 16

python -c 'import secrets; print(secrets.token_urlsafe(20))'

How to download a directory from FTP?

wget -r -l 10 --ask-password ftp://username@hostname/path

How to extend a partition in Ubuntu?

df -h  # find the name of the volume, e.g. /dev/mapper/ubuntu--vg-ubuntu--lv
lvextend -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv
resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv

How to use tar?

tar -czvf dir.tar.gz $some_dir
tar -xzvf dir.tar.gz

How to reset the root password in Ubuntu 22.04?

1. Boot into the GRUB menu
2. Press E to edit boot parameters
3. Replace ro quiet splash $vt_handoff with rw init=/bin/bash
4. Press CTRL + X or F10
5. Use mount | grep -w / to check for read and write access (/dev/sda5 on type ext4 (rw,realtime))
6. Use passwd to change the root password

Source: https://www.snel.com/support/how-to-reset-the-root-password-in-ubuntu-22-04/

How to calculate a checksum for a whole directory?

Using hashdeep:

md5deep -r -l ${DIRECTORY} | sort | md5sum

Python

How to configure Pyright to use .venv?

Create pyrightconfig.json in your project root:

{
    "venvPath": ".venv",
    "venv": ".",
    "pythonVersion": "3.12"
}

Reference: https://github.com/microsoft/pyright/blob/main/docs/configuration.md

Data

How to read Parquet files using DuckDB?

conda install duckdb-cli

SET autoinstall_known_extensions=1;
SET autoload_known_extensions=1;

SELECT * FROM 'test.parquet';

Reference: https://duckdb.org/docs/data/parquet/overview.html