Track 10 of 12
Utilities you build yourself
Six small tools, each built twice.
Intermediate 6 lessons Prerequisite: The shell in practice track, and either security fundamentals or networking for the later tools.
A password generator, an encoder, a checksum tool, a token inspector, a permissions converter and a subnet calculator. Each one exists twice: as something you can use, and as a lesson that shows you how to write it. Every one runs on commands the earlier tracks already gave you, and every one is a job people reach for a website to do.
By the end, you can build a small tool that does the job, and check its answers rather than trusting them.
Lessons in this track
- 01 Build a password generator Build a password generator in the shell, step by step, and count the bits behind every secret it prints.
- 02 Build an encoder and decoder Build an encoder and decoder in the shell, step by step, and learn to check a decode instead of trusting it.
- 03 Build a hash and checksum tool Grow a one-line sha256sum into a real checksum tool, step by step, then copy the finished script.
- 04 Build a JWT inspector Grow a single cut command into a token inspector, step by step, then copy the finished script.
- 05 Build a permissions calculator Read a mode from stat, turn octal into rwx and back, get the special bits right, and finish with a complete script you can keep.
- 06 Build a subnet calculator Convert an address to a number, build the mask, work out the network and broadcast with bitwise arithmetic, and finish with a complete script you can keep.