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macOS & Linux Basics

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CompTIA A+ 220-1201 & 220-1202

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1 Introduction & Exam Overview

About the CompTIA A+ Certification Exam Domains & Study Strategy

2 Core 1 Domain 1: Mobile Devices (13%)

Laptop Hardware & Components Laptop Features & Display Types Mobile Device Connectivity & Accessories Mobile Operating System Features Mobile Device Synchronization & Data Transfer

3 Core 1 Domain 2: Networking (23%)

TCP/IP Fundamentals & the OSI Model Common Ports & Protocols Wireless Networking Standards Network Hardware & Devices Network Configuration & Internet Connections Network Types & Topologies

4 Core 1 Domain 3: Hardware (25%)

Cables & Connectors RAM Types & Storage Devices Motherboards, CPUs & Power Supplies Printers & Multifunction Devices Peripheral Devices & Expansion Cards Network Cable Tools & Testing

5 Core 1 Domain 4: Virtualization & Cloud Computing (11%)

Virtualization Concepts Cloud Computing Models & Services Client-Side Virtualization in Practice

6 Core 1 Domain 5: Hardware & Network Troubleshooting (28%)

CompTIA Troubleshooting Methodology Hardware Troubleshooting Network Troubleshooting Printer Troubleshooting Display & Mobile Device Troubleshooting

7 Core 2 Domain 1: Operating Systems (28%)

Windows Editions & Features Windows Administrative Tools & Utilities Windows Command Line & PowerShell macOS & Linux Basics Windows Networking & File Sharing Windows Installation & Upgrade Methods

8 Core 2 Domain 2: Security (28%)

Physical & Logical Security Measures Malware Types & Threat Mitigation Wireless & Network Security Encryption & Data Protection

9 Core 2 Domain 3: Software Troubleshooting (23%)

Windows OS Troubleshooting Mobile OS & Application Troubleshooting Browser & Application Troubleshooting

10 Core 2 Domain 4: Operational Procedures (21%)

Documentation & Change Management Backup & Recovery Methods Safety & Environmental Procedures Scripting & Remote Access Technologies Privacy, Licensing & Organizational Policies

macOS & Linux Basics

Key Takeaways Explain This Topic AI

macOS defaults to the APFS file system (since High Sierra, 2017), uses Time Machine for incremental backups, FileVault for full-disk encryption, Spotlight (Cmd+Space) for search, and zsh as its default shell.

The Linux filesystem starts at root (/) with /home for users, /etc for configuration, /var for logs, /tmp for temporary files, /bin and /sbin for binaries, and /dev for device files.

Core Linux commands include ls, cd, pwd, cp, mv, rm, chmod, chown, grep, find, sudo, df, top, ps, kill, and man; sudo elevates a single command to root.

Linux octal permissions read owner-group-other with read=4, write=2, execute=1, so 755 = rwxr-xr-x and 644 = rw-r--r--; chmod sets them and chown changes ownership.

Package managers differ by distribution family: apt (Debian/Ubuntu), dnf/yum (Red Hat/Fedora), pacman (Arch), and zypper (SUSE).

Last updated: June 2026

macOS Essentials

The exam tests macOS by analogy to Windows — know the Apple equivalent of each Windows feature.

  • macOS feature Role / Windows analog
  • Finder File manager (= File Explorer)
  • Spotlight Universal search, Cmd+Space
  • Time Machine Automatic incremental backups to external/network disk
  • Mission Control All open windows + virtual desktops (Spaces)
  • Keychain Stored passwords and certificates
  • FileVault Full-disk encryption (= BitLocker)
  • Terminal CLI, default shell is zsh
  • AirDrop Peer-to-peer file transfer between Apple devices
  • Gatekeeper Blocks unsigned/unidentified app installs
  • System Settings Config panel (= Control Panel)

APFS (Apple File System) has been the default since macOS High Sierra (2017) , adding native encryption, snapshots, space sharing, and crash protection; the older format was HFS+ (Mac OS Extended) . Useful shortcuts: Cmd+Q quits an app, Cmd+W closes a window, and Cmd+Option+Esc opens Force Quit (the macOS analog of Ctrl+Alt+Del).

Linux Filesystem Hierarchy

Linux is a single tree rooted at / — there are no drive letters. Each top-level directory has a defined role.

  • Path Contents
  • / Root of the entire tree
  • /home User home directories (/home/username)
  • /root The root user's home (not the same as /)
  • /etc System-wide configuration files
  • /var Variable data: logs in /var/log , mail, spool
  • /tmp Temporary files, often cleared on reboot
  • /bin, /sbin Essential user and system binaries
  • /usr User programs and libraries
  • /dev Device files (disks, terminals)
  • /proc Virtual filesystem of process/kernel info
  • /mnt, /media Manual and removable mount points
  • Essential Linux Commands
  • Command Purpose Example
  • ls / cd / pwd List / change / print directory ls -la
  • cp / mv / rm Copy / move / remove rm -rf dir/
  • mkdir / touch Make directory / empty file mkdir proj
  • cat / less / nano / vi View / edit text cat /etc/hostname
  • grep / find Search text / files grep error /var/log/syslog
  • sudo / su Elevate one command / switch user sudo apt update
  • chmod / chown Change permissions / ownership chmod 755 run.sh
  • df / du Disk space free / usage df -h
  • top / ps / kill Live processes / list / terminate kill -9 1234
  • ip addr / ping Network config / connectivity ip addr show
  • man Manual pages man chmod
  • Linux File Permissions

Permissions display as -rwxrwxrwx : a type character followed by three triplets for owner, group, and other . Each triplet combines read ( r=4 ), write ( w=2 ), and execute ( x=1 ).

  • Octal Symbolic Meaning
  • 777 rwxrwxrwx Everyone full (insecure)
  • 755 rwxr-xr-x Owner full; others read+execute
  • 644 rw-r--r-- Owner read+write; others read
  • 700 rwx------ Owner only, full
  • 600 rw------- Owner only, read+write

Worked example: chmod 640 report.txt gives the owner read+write (6), the group read (4), and everyone else nothing (0) — exactly rw-r----- . You can also use symbolic mode: chmod u+x app adds execute for the owner, chmod g-w file removes group write. chown alice:staff file reassigns owner to alice and group to staff .

Package Management

The right package tool depends on the distribution family — a common exam item.

  • Family Manager Install command
  • Debian / Ubuntu apt sudo apt install pkg
  • Red Hat / Fedora / CentOS dnf (yum) sudo dnf install pkg
  • Arch pacman sudo pacman -S pkg
  • SUSE zypper sudo zypper install pkg

Typical apt workflow: sudo apt update refreshes the package index, sudo apt upgrade updates installed packages, and sudo apt remove pkg uninstalls.

Cross-Platform Scenarios and Pitfalls

The exam tests macOS and Linux mostly as contrasts with Windows, so train yourself on the equivalences. When a ticket says a Mac user lost a file and wants yesterday's version, the answer is Time Machine , not System Restore. When a Mac will not install an app downloaded from the web and warns it is "from an unidentified developer," the gatekeeper of that behavior is literally Gatekeeper , adjusted under Privacy & Security — not antivirus and not a permissions error.

For full-disk encryption on a lost MacBook, the protective feature is FileVault , the direct analog of BitLocker, and like BitLocker it relies on a recovery key that must be stored safely.

Linux questions cluster around permissions and elevation . A user who runs a downloaded script and gets "Permission denied" most often lacks the execute bit ; the fix is chmod +x script.sh (or chmod 755 ), not editing the file. A user who can read but not modify a system file in /etc needs sudo , because those files are owned by root and writable only by root. Remember that sudo elevates a single command while su switches into another user's full session — a scenario that wants one administrative action favors sudo for least privilege.

The numeric permission logic is worth drilling: to grant the owner full control and lock everyone else out entirely you compute 7-0-0 = 700 ; to let a web server's group read a config but keep it secret from others you use 640 .

Package-manager mismatches are a classic distractor. A command that works on Ubuntu ( apt install ) will fail on a Red Hat or Fedora host, where the correct tool is dnf (or legacy yum); on Arch it is pacman -S . If a scenario shows apt failing with "command not found" on a CentOS server, the issue is the wrong package manager for the distribution, not a broken repository.

File-system gotcha: macOS uses APFS (or older HFS+) and Linux uses ext4 , so an external drive formatted NTFS can be read on a Mac but generally not written without third-party drivers. The truly universal choice for moving large files among Windows, macOS, and Linux is exFAT , which every modern OS can read and write and which has no 4 GB file-size limit.