A container’s filesystem is not a single block of disk space. It is a stack of read-only image layers with a thin writable layer placed on top when the container starts. Every file the image contains lives in the read-only layers, and every change the running container makes—writing a log, modifying a config, creating a…
Running a container is only half the job. Knowing what it is actually doing—what configuration it was created with, how much CPU and memory it is consuming, what processes it is running—requires a set of inspection commands that read metadata rather than run new operations. docker inspect returns the full JSON description of a container,…
Once a container is running, the next question is how to observe and interact with it. A container is isolated by design, so you cannot simply open a terminal into it or read its output from the host. Docker provides three commands for this: docker logs retrieves the output a container has already produced, docker…
A container’s lifecycle is not limited to starting and stopping. Docker provides operations for pausing a running container without terminating it, resuming a paused container, restarting a container with a fresh process, and controlling the signals that govern how a container’s main process terminates. These operations matter because they determine what happens to in-flight work,…
The Docker CLI is the primary interface for managing containers. Four commands form the core of daily container work: docker run creates and starts a container from an image, docker ps lists containers and their states, docker stop gracefully terminates a running container, and docker rm removes a container from the system. These four operations…
Rust provides three loop constructs: loop, while, and for. Each serves a different purpose, and the choice among them is not arbitrary. loop repeats forever until an explicit break exits, and it can return a value from the break. while repeats as long as a condition is true. for iterates over the elements of an…
Control flow determines which code runs under which conditions. Rust’s if expression is the primary tool for branching, and it differs from the if of most languages in one important way: it is an expression, not a statement. This means it produces a value, and that value can be assigned to a variable, returned from…
The distinction between statements and expressions is the single most important syntactic concept in Rust. It explains why function bodies work the way they do, why if and match can produce values, why a stray semicolon changes a return type, and why let cannot appear on the right-hand side of an assignment. Every Rust programmer…
Functions are the building blocks of Rust programs. Every Rust program has at least one — main — and most programs are organized as a collection of functions that call each other. A function packages a sequence of statements behind a name, accepts inputs as parameters, produces an output as a return value, and can…
Rust’s scalar types hold a single value. Compound types group multiple values into one. The two primitive compound types are tuples and arrays. Both have a fixed size known at compile time, and both store their elements contiguously, but they differ in a crucial way: a tuple can hold values of different types, while an…