Blog
Thoughts on engineering, design, and building great products.
Users, Groups and sudo
Linux is multi-user by design. This article explains where users and groups are stored (/etc/passwd, /etc/shadow, /etc/group), how to create and manage them, and why you should use sudo instead of logging in directly as root.
Permissions: User, Group, and chmod
A deep dive into Linux's permission mechanism: reading the rwx string, the three groups user/group/other, octal notation, changing permissions with chmod (octal and symbolic), changing ownership with chown, and the umask that decides default permissions.
Optimizing Images: Multi-Stage Builds and Security
Large images slow down deploys and widen the attack surface. This article shrinks images with multi-stage builds (real example: 301MB down to 15.4MB), picks lean base images, runs non-root, and avoids baking in secrets.
Open an AWS Account Safely and Set Up a Billing Alert
Create an AWS account the right way: enable MFA on the root account, create an IAM user for daily use, install the AWS CLI, and set a Budget so no bill catches you off guard.
VPC and Security Group: Networking and Basic Firewalling on AWS
Understand VPC, public/private subnets, route tables, and Security Groups. Know why your server lets some in and not others, and how to tighten access correctly.