# Linux Command Line Foundations for Makers

Learn enough shell navigation, reading, and command composition to inspect a project machine without blindly pasting commands.

## Outcome
Open a terminal, find files, read output, and run small inspection commands with confidence.

## Safe first step
pwd, ls, and cat tell you where you are and what file you are reading before you change anything.

## Ladder steps
### 1. Know the current directory
Start by proving where the shell is pointed.

Check: Use pwd before running path-sensitive commands.

### 2. List before opening
Use ls variants to inspect names, types, sizes, and timestamps.

Check: Explain why a file or directory is the next target.

### 3. Read small files
Use cat, less, and head for text inspection.

Check: Do not dump huge logs blindly.

### 4. Pipe one answer into the next
Use a pipe when the second command filters the first command's output.

Check: Name what each side of the pipe contributes.

## Examples
### Show the current working directory
```sh
pwd
```
Expected signal: An absolute path such as /srv/www/topicladder.com/current

### List files with sizes and hidden entries
```sh
ls -lah
```
Expected signal: Permissions, owner, size, and timestamp columns

### Read only the first lines of a file
```sh
head -40 README.md
```
Expected signal: A small preview instead of a full dump

## Common traps
- Running a command in the wrong directory.
- Using sudo because the first attempt failed.
- Copying a pipeline before understanding each command.

## Practice task
Create a small folder with two text files. Use pwd, ls -lah, head, and grep to answer where the files are and what each contains.

## Next steps
- Learn file permissions.
- Learn log search.
- Deploy a static site with Nginx.

## Related
- [LinuxOneLiners command library](https://linuxoneliners.com/commands/)