Linux and Unix Command Line: A Practical Introduction

Repeat practice on the Linux and Unix command line to reinforce memory of core features and shell programming, with real-world use across flavors like Xenix and AIX.

Set up a lab practice environment on a Windows 11 host by downloading and installing Oracle VirtualBox 7.1.4, then run CentOS Stream 9 as a guest in a VirtualBox VM.

Download the CentOS Stream 9 iso image and start the download process. Note that the iso image is about 11.8 gb and the download will take some time.

Explore the Linux and Unix command line by examining the root directory and its subdirectories, and learn commands like pwd, cd, vi, and how to access help.

Explore root versus non-root users in Linux and Unix, and learn to log in as a regular user and escalate with sudo or switch to root for administration.

Explore the general syntax of Linux and Unix commands, including prompts, options, and arguments; learn to use commands like pwd, ls, and cat.

Learn how to use the pwd command to report your present working directory and verify it with a subsequent cd navigation to a target path such as /var/tmp.

Identify the active user with the id command and view user details, then list logged-in sessions with the who command, and understand that cd navigates to the home directory.

Demonstrates using the date and cal commands to report time and calendars, with default outputs and customizable format specifiers like %m, %D, %Y, and %H.

Learn how the ls command lists the present directory contents, how pwd shows the present working directory, and how ls -l reveals file attributes and marks directories with d.

Explains the dot and dot dot as the current directory and the parent directory in relative paths. Contrasts relative and absolute paths using cd and pwd.

Learn how to use the mkdir command to create directories with relative and absolute paths, including making intermediate directories with the -p option, and verify with ls and pwd.

Learn how to use cat and tac commands to read and reverse order lines in text files, create and view files, and display non-printable characters with cat -v.

Learn how the more command reads long text files by paging content, compare it with cat, and navigate pages using enter, space, back, and quit.

Master the ls command: reveal hidden files with -a, use -l and -h for detailed, human-readable listings, and sort by name, size, or time, including recursive and directory listings.

Explore how the head and tail commands read the first or last lines of a text file, defaulting to ten lines, with options like -n and +start for shell scripting.

Master renaming and moving files and directories with the mv command, including interactive and non-interactive behaviors and overwrite risks.

Explore linux and unix shells, their roles and features, including bash as the default login shell. Learn command execution, redirection, pipes, metacharacters, quoting, and tools like find, grep, and ls.

Survey linux and unix shells, including sh, csh, tcsh, bash, ksh, and zsh, highlighting features like array variables, select loop, bourne compatibility, and switching with PS and echo dollar dollar.

Explain how external commands live as binary executables in /usr/bin and how shell built-ins, such as exit and export, are contained within the shell.

Explore the bash shell, a GNU/Linux compatible successor to sh, and discover features like array variables, select loops, tab completion, and command history for interactive terminal use.

Master shell metacharacters such as the star, question mark, tilde, and dash, and apply them to pattern matching, file and directory listing, and navigation.

Explore quoting mechanisms in the shell, including single quotes, double quotes, and backticks, and learn how escape characters and metacharacters such as the asterisk, question mark, and dollar affect output.

Master working with local and environment variables, export, unset, and explore reserved and special shell variables like PS1, PS2, and PATH in the Linux and Unix shell.

Explore shell aliases in the Linux and Unix command line by creating single-command shortcuts, combining multiple commands, and enforcing interactive prompts with rm, cp, and mv aliases.

Learn to write and execute shell scripts, building on your Linux and Unix command line knowledge. Explore shebang lines, input/output, conditional execution, loops, and shell script permissions.

Explore loop constructs in shell scripts, including for, while, and until loops, with conditional tests, break and continue, and practical examples.