macOS & Linux Basics

A+ Core 2 — 220-1102 | Domain 1.5, 1.6

macOS preferences, iCloud, and common features. Linux filesystem hierarchy, shell commands, file permissions, and package management. Both are tested on 220-1102 Domain 1.

18 Slides Domain 1.5 & 1.6 macOS • Linux Shell • Permissions • Packages Exam 220-1102

Slide 2 of 18

macOS Overview

Unix-based, POSIX-compliant OS developed by Apple. Built on Darwin (BSD kernel + Mach).

System Preferences / Settings

macOS equivalent of Windows Control Panel. Ventura and later renamed it "System Settings." Contains displays, sound, network, users, security, and accessibility controls. Accessed via Apple menu or Spotlight.

Finder

Default file manager. Shows files, folders, network shares, and connected devices. iCloud Drive files appear in Finder alongside local files. Column view, gallery view, and list view are available.

Spotlight

System-wide search (Cmd + Space). Searches files, applications, contacts, calendar, web, and performs calculations. Equivalent to Windows Search + Run combined. Fastest way to launch any app or setting.

Mission Control & Spaces

Mission Control (F3 or swipe up) shows all open windows and virtual desktops (Spaces). Multiple Spaces allow users to organize work across virtual screens. Analogous to Windows virtual desktops.

Keychain Access

macOS password manager storing Wi-Fi passwords, website credentials, certificates, and encryption keys. Integrated with Safari and most macOS apps. Syncs across Apple devices via iCloud Keychain.

Slide 3 of 18

macOS Key Features

iCloud integration, Time Machine, FileVault, and Gatekeeper are all A+ exam topics.

iCloud

Apple's cloud sync service. Syncs Desktop, Documents, Photos, Contacts, Calendar, and Keychain across all Apple devices. iCloud Drive provides cloud storage accessible from Finder. Requires Apple ID; not tied to local domain accounts.

Time Machine

Automatic hourly, daily, and weekly backups to an external drive or Time Capsule. Allows file-level restore from any backup snapshot. Full system restore from boot recovery mode. The macOS equivalent of Windows Backup and Restore.

FileVault

Full disk encryption for macOS. AES-128 encryption of the startup volume. Recovery key generated at setup — must be stored securely. Without the key, encrypted data is unrecoverable. Managed via System Preferences > Security & Privacy.

Gatekeeper

Controls which applications can run. Settings: App Store only, App Store and identified developers, anywhere (not recommended). Prevents execution of unsigned or malicious software. Bypass requires explicit user override in Security settings.

System Integrity Protection (SIP)

Restricts root-level access to protected system directories even for admin users. Prevents malware and misconfigured apps from modifying critical system files. Can only be disabled by booting into Recovery Mode.

Terminal

Full Unix command-line interface. Runs bash or zsh (default since Catalina). Provides access to the entire underlying Unix system. Required for many advanced administration tasks not exposed in the GUI.

Slide 4 of 18

macOS Admin Tools

The macOS equivalents of Windows administrative tools you already know.

macOS Tool	Location / Access	Windows Equivalent
Activity Monitor	Applications / Utilities	Task Manager
Disk Utility	Applications / Utilities	Disk Management
Console	Applications / Utilities	Event Viewer
Network Utility	Applications / Utilities (legacy)	Network diagnostics tools
System Information	About This Mac > System Report	msinfo32 / Device Manager
Directory Utility	Applications / Utilities	Active Directory Users & Computers
Keychain Access	Applications / Utilities	Credential Manager

Exam Tip

The A+ exam frequently asks you to match macOS tools to their Windows counterparts. Activity Monitor = Task Manager is the most commonly tested pair. Disk Utility handles partitioning, formatting, first aid (disk repair), and RAID — it does more than just Disk Management.

Slide 5 of 18

Linux Overview

Open-source, Unix-like OS kernel created by Linus Torvalds in 1991. Distributions vary the package around the same kernel.

Distributions (Distros)

A Linux distribution bundles the kernel with package management, init system, desktop environment, and default applications. Debian/Ubuntu, RHEL/CentOS/Fedora, and Arch are the major families. A+ focuses on concepts that apply across all distros.

Shell

Command-line interpreter. bash (Bourne Again Shell) is the default on most distros. zsh is the default on macOS. sh, ksh, and fish are alternatives. All accept the same POSIX core commands. The shell is the primary administration interface.

Everything Is a File

In Linux, devices, network sockets, and processes are represented as files in the filesystem. /dev/sda is your first hard disk. /proc contains running process information. This abstraction makes scripting and administration consistent across all resource types.

Root vs Sudo

Root (UID 0) is the superuser account with unrestricted access. Most distros disable direct root login and instead use sudo (substitute user do), which allows authorized users to execute commands with root privileges while maintaining an audit trail.

Case Sensitivity

Linux filesystems are case-sensitive. "File.txt" and "file.txt" are two different files. Commands are also case-sensitive: "ls" works; "LS" does not. This is a frequent source of errors for technicians coming from Windows.

Slide 6 of 18

Linux Filesystem Hierarchy

FHS (Filesystem Hierarchy Standard) defines where everything lives.

Directory	Purpose
/	Root of the entire filesystem
/bin	Essential user binaries (ls, cp, mv, bash)
/etc	System-wide configuration files
/home	User home directories (/home/alice)
/usr	User-installed programs and libraries
/var	Variable data: logs (/var/log), web (/var/www)
/tmp	Temporary files; cleared on reboot
/dev	Device files (/dev/sda, /dev/null)
/proc	Virtual filesystem; running process info
/root	Home directory for the root user

Slide 7 of 18

File Permissions

rwxr-xr-x decoded: three groups of three bits, four numeric values you must know.

Real-World Permission Examples

Permission	Octal	Meaning	Real Example
rwxr-xr-x	755	Owner: full. Others: read+execute	A bash script everyone can run but only you can edit
rw-r--r--	644	Owner: read+write. Others: read only	A config file like /etc/hostname — readable by all, editable by root
rw-------	600	Owner only. No one else sees it	SSH private key (~/.ssh/id_rsa) — SSH refuses if others can read it
rwx------	700	Owner: full. Others: nothing	Your home directory /home/alice — private workspace
rwxrwxr-x	775	Owner+group: full. Others: read+exec	Shared project folder — the dev team edits, others browse

chmod (change mode)

chmod 755 deploy.sh — makes a script executable.
chmod u+x script.py — adds execute for owner only.
chmod -R 644 /var/www — recursively sets read-only for web files.

chown (change owner)

chown alice:devs project/ — sets owner to alice, group to devs.
chown -R www-data:www-data /var/www — web server owns its files.
Only root can change file ownership.

Exam Trap

SSH will refuse to use a private key if its permissions are too open. If chmod 644 ~/.ssh/id_rsa — SSH fails. Must be chmod 600. This is a common exam scenario question.

Slide 8 of 18

Essential Linux Commands

The commands the A+ exam tests you on — navigation, files, and system info.

Navigation & Files

                    # Print working directory

                    pwd

                    # List files (long, all, human sizes)

                    ls -lah

                    # Change directory

                    cd /etc

                    # Copy, move, remove

                    cp src.txt dst.txt

                    mv old.txt new.txt

                    rm -rf /path/to/dir

                    # Make directory

                    mkdir -p /path/new

System & Text

                    # View file contents

                    cat /etc/passwd

                    less /var/log/syslog

                    # Search in files

                    grep "error" /var/log/syslog

                    # Disk usage

                    df -h

                    du -sh /var/log

                    # Process list

                    ps aux

                    top

Exam Tip

Know the difference between absolute paths (/etc/passwd always works) and relative paths (../etc/passwd depends on current directory). The exam frequently tests ls -la vs ls -l and the meaning of the permissions column output.

Slide 9 of 18

Package Management

apt for Debian/Ubuntu, yum/dnf for RHEL/CentOS — same concept, different commands.

Action	apt (Debian/Ubuntu)	yum / dnf (RHEL/CentOS)
Update package list	apt update	yum check-update
Upgrade installed packages	apt upgrade	yum update
Install a package	apt install nginx	yum install nginx
Remove a package	apt remove nginx	yum remove nginx
Search for a package	apt search keyword	yum search keyword
Show package info	apt show nginx	yum info nginx

Package Repositories

Packages are downloaded from configured repositories (repos). Repos are listed in /etc/apt/sources.list (Debian) or /etc/yum.repos.d/ (RHEL). Official repos are maintained by the distro; third-party repos can be added for additional software.

Dependencies

Package managers automatically resolve and install dependencies. Installing nginx installs OpenSSL, pcre, and other required libraries automatically. Manual compilation (./configure, make, make install) does not handle dependencies.

Slide 10 of 18

Linux User Management

/etc/passwd, /etc/shadow, /etc/group — the three files that define every user.

useradd / usermod / userdel

useradd -m -s /bin/bash alice: creates user with home directory and bash shell. usermod -aG sudo alice: adds alice to the sudo group. userdel -r alice: removes user and their home directory. All changes write to /etc/passwd and /etc/shadow.

passwd Command

passwd alice: sets alice's password (must be root). passwd: changes your own password. passwd -l alice: locks the account. passwd -u alice: unlocks it. Password hashes are stored in /etc/shadow, readable only by root.

Groups

groupadd devs: creates a group. usermod -aG devs alice: adds alice to devs (append, don't replace). groups alice: lists alice's groups. Files owned by a group are accessible to all group members per the group permission bits.

            # /etc/passwd format: username:x:UID:GID:comment:home:shell

            alice:x:1001:1001:Alice Smith:/home/alice:/bin/bash

            # x means password hash is in /etc/shadow (not shown here)

            # UID 0 = root | UID 1-999 = system accounts | UID 1000+ = regular users

Slide 11 of 18

Linux Networking Commands

Core tools for diagnosing and configuring network from the Linux shell.

Command	Purpose	Example
ip addr	Show IP addresses and interfaces (replaces ifconfig)	ip addr show eth0
ip route	Show / modify routing table	ip route show
ping	ICMP reachability test	ping -c 4 8.8.8.8
traceroute	Hop-by-hop path to destination	traceroute google.com
ss	Socket statistics (replaces netstat)	ss -tulnp
dig / nslookup	DNS query and troubleshooting	dig google.com A
curl / wget	HTTP/HTTPS requests; file download	curl -I https://example.com

ifconfig vs ip

ifconfig is deprecated on modern Linux distros but still present on many systems and may appear on the exam. The ip command is the current replacement. Both output IP address, subnet mask, and MAC address for each interface.

Slide 12 of 18

Services & systemd

systemctl is the primary tool for managing services on modern Linux distributions.

Common systemctl Commands

                    # Start / stop a service

                    systemctl start nginx

                    systemctl stop nginx

                    systemctl restart nginx

                    # Enable / disable at boot

                    systemctl enable nginx

                    systemctl disable nginx

                    # Check status

                    systemctl status nginx

                    # List all running services

                    systemctl list-units --type=service

Service States

active (running), inactive (stopped), failed (error on start), enabled (starts at boot), disabled (does not start at boot). A service can be enabled but currently stopped, or running but disabled (will not survive reboot).

Logs with journalctl

journalctl -u nginx: service-specific logs. journalctl -b: logs since last boot. journalctl -f: follow (tail -f equivalent). Replaces reading /var/log directly for systemd-managed services.

Slide 13 of 18

macOS vs Linux Comparison

Both are Unix-based but differ significantly in administration, licensing, and ecosystem.

Attribute	macOS	Linux
Kernel	Darwin (XNU, BSD + Mach)	Linux kernel (Torvalds)
Default Shell	zsh (Catalina+)	bash (most distros)
Package Manager	Homebrew (third-party); App Store	apt, yum/dnf, pacman (distro-dependent)
Filesystem	APFS (primary), HFS+ (legacy)	ext4 (primary), XFS, Btrfs, ZFS
GUI Desktop	Aqua (proprietary)	GNOME, KDE, XFCE, and many others
Hardware	Apple hardware only (officially)	Runs on virtually any x86/ARM hardware
Licensing	Proprietary; bundled with hardware	Open source (GPL); free to use and modify
Enterprise Domain Join	Active Directory via Directory Utility	sssd or winbind for AD; native LDAP

Slide 14 of 18

Linux Log Files

Logs are the primary troubleshooting tool on Linux. Know where each type lives.

Log File	Contents
/var/log/syslog	General system messages (Debian/Ubuntu)
/var/log/messages	General system messages (RHEL/CentOS)
/var/log/auth.log	Authentication attempts, sudo usage, SSH logins (Debian/Ubuntu)
/var/log/secure	Authentication (RHEL/CentOS equivalent of auth.log)
/var/log/kern.log	Kernel messages; hardware driver issues
/var/log/dmesg	Boot-time kernel ring buffer; hardware detection
/var/log/apt/history.log	Package install/remove history

Reading Logs

tail -f /var/log/syslog: follow in real time. grep "Failed password" /var/log/auth.log: filter for failed SSH attempts. less /var/log/kern.log: paginate a large log file. All three are essential diagnostic patterns.

Log Rotation

logrotate automatically compresses and archives logs on a schedule defined in /etc/logrotate.conf and /etc/logrotate.d/. Without rotation, /var/log fills the disk. Current log: syslog. Prior: syslog.1. Compressed: syslog.2.gz.

Slide 15 of 18

Shell Scripting Basics

Automate repetitive tasks. The A+ exam tests recognition, not development of scripts.

                #!/bin/bash

                # Shebang — tells OS which interpreter to use

                NAME="forge-backup"

                DATE=$(date +%Y-%m-%d)

                # Conditional

                if [ -d /backup ]; then

                    echo "Backup dir exists"

                else

                    mkdir -p /backup

                fi

                # Loop

                for FILE in /etc/*.conf; do

                    cp "$FILE" /backup/

                done

                echo "Backup complete: $DATE"

Shebang Line

#!/bin/bash on line 1 tells the OS to execute the script with bash. Without it, the script runs in the current shell, which may differ. Always include the shebang.

Execute Permission

A script file needs execute permission before it can run: chmod +x script.sh. Then: ./script.sh or bash script.sh. The exam tests this permission requirement.

Exit Codes

Every command returns an exit code: 0 = success, non-zero = failure. Check with $? immediately after a command. Used in if statements: if [ $? -eq 0 ]; then...

Slide 16 of 18

Disk & Filesystem Commands

Format, mount, and check disks from the command line.

Command	Purpose	Example
lsblk	List all block devices and partitions	lsblk -f
fdisk	Partition table manipulation	fdisk /dev/sdb
mkfs	Format partition with filesystem	mkfs.ext4 /dev/sdb1
mount	Mount a filesystem to a directory	mount /dev/sdb1 /mnt/data
umount	Unmount a filesystem	umount /mnt/data
fsck	Check and repair filesystem	fsck /dev/sda1 (unmounted)
df -h	Disk free space per filesystem	df -h
du -sh	Disk usage of a directory	du -sh /var/log

Persistent Mounts

Mounts made with the mount command do not survive reboot. To persist a mount, add it to /etc/fstab with the device, mount point, filesystem type, options, dump, and pass fields. The exam expects you to know that /etc/fstab controls what mounts at boot.

Slide 17 of 18

macOS Command Line

macOS Terminal runs zsh by default and shares most commands with Linux.

Command	macOS Behavior / Notes
ls, cd, cp, mv, rm	Identical behavior to Linux
diskutil	macOS disk management CLI (equivalent of Disk Utility GUI). diskutil list, diskutil eraseDisk, diskutil repairVolume
networksetup	Configure network settings from CLI. networksetup -setdnsservers Wi-Fi 8.8.8.8
softwareupdate	Install macOS updates from CLI. softwareupdate -ia installs all available updates
system_profiler	Machine hardware and software info. system_profiler SPHardwareDataType
launchctl	Manage launch agents and daemons (macOS equivalent of systemctl)
defaults	Read/write macOS preference plist files. defaults write com.apple.dock autohide -bool true

An M1 MacBook Pro is not applying the latest macOS update through the GUI. You SSH in remotely and run: sudo softwareupdate -ia --restart. The update installs and the system reboots. Terminal access is essential for headless or remote macOS administration.

Slide 18 of 18

Domain 1.5 & 1.6 Key Facts

macOS & Linux Basics — condensed for exam review.

1

macOS = Darwin kernel (BSD + Mach). Time Machine = backup. FileVault = encryption. Gatekeeper = app trust. Spotlight = search + run.

2

Activity Monitor = Task Manager. Disk Utility = Disk Management. Console = Event Viewer. These mappings appear directly on the exam.

3

Linux FHS: / root, /bin binaries, /etc config, /home users, /var logs/web, /tmp temp, /dev devices, /proc process info.

4

File permissions: r=4, w=2, x=1. rwxr-xr-x = 755. chmod 644 = rw-r--r--. chown sets ownership. chmod sets permissions.

5

Package management: apt (Debian/Ubuntu), yum/dnf (RHEL). apt install, apt update, apt upgrade are the three you must know.

6

systemctl manages services: start, stop, restart, enable (boot), disable, status. journalctl -u service reads logs.

7

Linux is case-sensitive. /etc/Passwd and /etc/passwd are different. All commands are lowercase. Absolute paths start with /; relative paths do not.

8

Scripts need execute permission: chmod +x script.sh. Shebang #!/bin/bash on line 1 specifies the interpreter. Exit code 0 = success.

macOS & Linux Basics | A+ Core 2