--- title: "Glossary: Terminal & Unix Terms Explained" description: "Your friendly guide to terminal, shell, and Unix terminology. Bite-sized explanations of POSIX commands, shell concepts, and Caro features for everyone." url: "https://caro.sh/glossary" markdown_url: "https://caro.sh/glossary.md" lang: "en" type: "website" image: "https://caro.sh/og/glossary.png" --- Terminal Galore # The Friendly Terminal Glossary Unix & shell concepts made simple Whether you're just starting your terminal journey or brushing up on fundamentals, this glossary breaks down commands, concepts, and Caro features into easy-to-digest bites. **Terminal knowledge for everyone.** [Caro](https://caro.sh/glossary#caro-terms) [Shell Basics](https://caro.sh/glossary#shell-basics) [Files & Dirs](https://caro.sh/glossary#file-commands) [Text Processing](https://caro.sh/glossary#text-processing) [Permissions](https://caro.sh/glossary#permissions) [Processes](https://caro.sh/glossary#processes) [Networking](https://caro.sh/glossary#networking) [Shortcuts](https://caro.sh/glossary#shortcuts) 🥕 ## Caro Terms Understanding your AI shell companion ### Caro Core Your AI-powered shell command assistant. Caro translates natural language into safe, executable shell commands. Think of it as having a Unix expert by your side. `caro "find all large files over 100MB"` ### Safety Validation Safety Caro's built-in protection that analyzes commands before execution. It catches dangerous patterns like `rm -rf /` and asks for confirmation on risky operations. ### Backend Config The AI engine powering Caro's language understanding. Options include local models (Ollama, MLX) for privacy or cloud APIs (Claude, OpenAI) for power. ### Dry Run Safety Preview mode that shows what a command would do without actually executing it. Perfect for learning or verifying complex operations. `caro --dry-run "delete all temp files"` ### Interactive Mode Feature A conversational shell session where you can ask follow-up questions, refine commands, and explore options naturally. ### Local Inference Privacy Running AI models directly on your machine. Your commands and data never leave your computer—perfect for sensitive work environments. 🐚 ## Shell Basics The foundation of command-line mastery ### Shell Essential The program that interprets your commands. Common shells include **bash**, **zsh**, and **fish**. It's the interface between you and the operating system. ### Terminal Essential The window application that displays your shell. Examples: Terminal.app, iTerm2, Windows Terminal, or Alacritty. The terminal is the container; the shell runs inside it. ### CLI Acronym **Command Line Interface**. Any program you interact with by typing commands rather than clicking. Git, npm, docker—all CLIs. ### POSIX Standard **Portable Operating System Interface**. A set of standards ensuring commands work consistently across Unix-like systems (Linux, macOS, BSD). ### Prompt UI The text that appears before your cursor, indicating the shell is ready for input. Often shows username, hostname, and current directory: `user@host:~$` ### PATH Environment An environment variable listing directories where the shell looks for executable programs. When you type `git`, the shell searches PATH to find it. `echo $PATH` ### Environment Variable Concept Named values available to all programs. Used for configuration like API keys, paths, and preferences. Access with `$VARIABLE_NAME`. `export MY_VAR="hello"` ### Alias Shortcut A custom shortcut for a longer command. Define frequently used commands once, use a short name forever. `alias ll="ls -la"` 📁 ## Files & Directories Navigate and manage your filesystem ### ls Command **List** directory contents. The first command everyone learns. `ls -la` List all files with details ### cd Command **Change Directory**. Navigate between folders. `cd ~/Documents` Go to Documents folder ### pwd Command **Print Working Directory**. Shows your current location. `pwd` Output: /home/user/projects ### mkdir Command **Make Directory**. Create new folders. `mkdir -p path/to/new` Create nested directories ### rm Command **Remove**. Delete files or directories. *Use with caution!* `rm -i file.txt` Delete with confirmation ### cp Command **Copy**. Duplicate files or directories. `cp -r src/ dest/` Copy directory recursively ### mv Command **Move**. Relocate or rename files/directories. `mv old.txt new.txt` Rename a file ### touch Command Create empty files or update timestamps. `touch newfile.txt` Create empty file ### find Command Search for files by name, type, size, date, and more. `find . -name "*.js"` Find all JavaScript files **Pro Tip:** Use `~` for home directory, `.` for current, `..` for parent, and `-` for previous directory. 📝 ## Text Processing Search, filter, and transform text like a pro ### cat Command **Concatenate**. Display file contents or combine multiple files. `cat file.txt` Show file contents ### grep Command **Global Regular Expression Print**. Search text using patterns. One of the most powerful Unix tools. `grep -r "TODO" ./src` Find all TODOs in source code ### sed Command **Stream Editor**. Find and replace text, or transform streams with powerful pattern matching. `sed 's/old/new/g' file` Replace all occurrences ### awk Command A complete text-processing language. Extract columns, compute values, and format output from structured data. `awk '{ print $1 }' file` Print first column ### head / tail Command View the beginning or end of files. Great for logs and large files. `tail -f app.log` Follow log in real-time ### sort / uniq Command Sort lines and filter duplicates. Often used together in pipelines. `sort file | uniq -c` Count unique lines ### wc Command **Word Count**. Count lines, words, and bytes in files. `wc -l *.txt` Count lines in all text files ### Pipe ( | ) Operator Connect commands together. Output of one command becomes input to the next. The secret sauce of Unix philosophy. `cat log | grep error | wc -l` Count error lines in log 🔐 ## Permissions & Ownership Control who can do what with your files ### chmod Command **Change Mode**. Modify file permissions (read, write, execute) for owner, group, and others. `chmod +x script.sh` Make script executable ### chown Command **Change Owner**. Transfer file ownership to another user or group. `chown user:group file` Change owner and group ### sudo Command **Superuser Do**. Run commands with administrator privileges. With great power comes great responsibility. `sudo apt update` Update as administrator ### Permission Numbers Concept Octal notation for permissions: **4**=read, **2**=write, **1**=execute. Combine for each group (owner/group/others). `chmod 755 script.sh` rwxr-xr-x (owner all, others read+execute) #### Quick Permission Reference 777 Everyone can do everything (rarely safe) 755 Owner all, others read & execute (executables) 644 Owner read & write, others read (files) 600 Owner only read & write (private files) ⚙️ ## Processes & Jobs Manage running programs and background tasks ### ps Command **Process Status**. List running processes and their details. `ps aux | grep node` Find all Node.js processes ### top / htop Command Real-time process monitor. See CPU, memory usage, and manage processes interactively. htop is the colorful modern version. ### kill Command Send signals to processes. Commonly used to terminate misbehaving programs. `kill -9 12345` Force kill process 12345 ### Background (&) Operator Run a command in the background, freeing up your terminal for other work. `npm run dev &` Start server in background ### Ctrl+Z / fg / bg Shortcuts **Ctrl+Z** suspends current process. **fg** brings it back to foreground. **bg** resumes it in background. ### nohup Command **No Hangup**. Keep process running after you close the terminal. `nohup ./server &` Run server persistently 🌐 ## Networking Connect, transfer, and debug network operations ### curl Command Transfer data from or to a server. The Swiss Army knife of HTTP requests. `curl -X POST -d '{key":"val}' url` Send JSON POST request ### wget Command Download files from the web. Great for fetching resources and mirroring sites. `wget -O file.zip url` Download with custom filename ### ssh Command **Secure Shell**. Connect to remote machines securely. The backbone of server administration. `ssh user@hostname` Connect to remote server ### scp Command **Secure Copy**. Transfer files between machines over SSH. `scp file.txt user@host:/path` Copy file to remote server ### ping Command Test network connectivity to a host. Sends packets and measures response time. `ping google.com` Check internet connectivity ### netstat / ss Command Display network connections, routing tables, and port usage. `ss` is the modern replacement for `netstat`. `ss -tulpn` Show listening ports ⌨️ ## Keyboard Shortcuts Speed up your terminal workflow ### Navigation `Ctrl` + `A` Move to beginning of line `Ctrl` + `E` Move to end of line `Alt` + `B` Move back one word `Alt` + `F` Move forward one word ### Editing `Ctrl` + `U` Delete to beginning of line `Ctrl` + `K` Delete to end of line `Ctrl` + `W` Delete previous word `Ctrl` + `Y` Paste deleted text (yank) ### Control `Ctrl` + `C` Cancel current command `Ctrl` + `D` Exit shell / End of input `Ctrl` + `L` Clear screen `Ctrl` + `Z` Suspend process ### History `↑` / `↓` Previous / Next command `Ctrl` + `R` Search command history `!!` Repeat last command `!$` Last argument of previous command ## Ready to Put This Knowledge to Use? Let Caro translate your natural language into perfectly crafted shell commands. No more memorizing syntax—just describe what you want to do. [Try Caro ](https://caro.sh/)[Explore Features](https://caro.sh/explore)