1.11 - Common Linux commands
CompTIA A+ Core 2 objective 1.11 covers the common Linux commands a technician should recognise. chmod changes a file's permissions. On Debian and Ubuntu systems, apt installs software packages. df displays free and used disk space on mounted filesystems. On modern distributions, the ip command shows or configures network interfaces (for example, ip addr), replacing the older ifconfig. Knowing what each command does lets you pick the right one for a described task. Expect short scenario questions that state a goal - change permissions, install a package, check disk space, view network interfaces - and ask which Linux command to run. Because Linux underpins servers, containers and Android, these basics come up often on the job as well as on the exam.
Change permissions = chmod. Install a package (Debian/Ubuntu) = apt. Disk space free/used = df. Show/configure network interfaces = ip (e.g. ip addr, replaces ifconfig).
Practice questions
1. Which Linux command installs software packages on Debian/Ubuntu systems?
- chmod
- apt (correct answer)
- grep
- kill
apt (apt-get) manages packages on Debian/Ubuntu (install/update/remove). yum/dnf are used on RHEL/Fedora.
2. Which Linux command changes a file's permissions?
- The ls command
- The chmod command (correct answer)
- The grep command
- The pwd command
chmod sets read/write/execute permissions (e.g., chmod 755). ls lists, grep searches, pwd prints the path.
3. Which Linux command displays free and used disk space on mounted filesystems?
- ps
- df (correct answer)
- kill
- chmod
df reports filesystem disk usage. ps shows processes; kill ends a process; chmod sets permissions.
4. Which Linux command shows or configures network interfaces on modern distros?
- The chmod permissions command
- The ip command (e.g., ip addr) (correct answer)
- The grep text-search command
- The kill process command
The ip command (ip addr/ip link/ip route) manages interfaces/routes; ifconfig is the older equivalent.