City of Refuge Cybersecurity Analyst Training Class #11 Linux Student Success Workbook

Vocabulary flashcards covering core Linux operating system concepts, navigation commands, permissions, security principles, and utilities from the Class #11 Student Success Workbook.

Operating system

Software that manages a computer.

Linux

An operating system family based on the Linux kernel.

Distribution

A packaged Linux system, such as Ubuntu or Fedora.

Kernel

Core software connecting hardware and programs.

Terminal

Application for entering commands and providing command-line access.

Shell

Program that interprets typed commands.

Directory

A folder that holds files or other folders.

Path

Directions to a file or directory.

Root directory

The top-level / of the Linux filesystem.

root account

Highly privileged administrator account with powerful system privileges.

Permission

Rule governing access to files or directories.

Process

An instance of a running program.

Package manager

Tool for installing and updating software packages.

Log

Record of system or application events that provides evidence and troubleshooting information.

Service

Program that often runs in the background.

IP address

Address used by an interface on an IP network.

DNS

System that resolves domain names to IP addresses.

Port

Number that helps route traffic to a service.

SSH

Protocol for secure remote access.

Least privilege

Security principle of providing only the access required to do a task and limiting unnecessary permissions.

Authentication

Verification of identity that asks: Who are you?

Authorization

Determination of permitted actions that asks: What can you access?

Pipe (|)

Symbol connecting command output to another command as input.

Redirection (>)

Sending command output to a file or elsewhere, which can overwrite data.

pwd

Command that prints the current working directory.

ls

Command that lists directory contents.

cd

Command that changes directory.

Parent directory (..)

Directory navigation reference represented by .. indicating the directory above the current one.

Home directory (~)

Directory represented by ~ that expands to your home directory in common shells.

mkdir

Command that creates a directory.

cat

Command commonly used to display or print short text file content.

cp

Command used to copy files or directories with appropriate options.

mv

Command used to move or rename files.

rm

Command that removes files, requiring caution because it permanently deletes files and recovery may be difficult.

ls -a

Option and command that includes hidden entries when listing directory contents.

grep

Command that searches for matching text patterns.

find

Command that locates files by name or criteria.

Read permission (r)

Permission setting that denotes read access.

Write permission (w)

Permission setting that denotes write access.

Execute permission (x)

Permission setting that denotes execute access.

Standard Unix permission groups

The three entity categories for which permissions are described: owner, group, and others.

chmod

Command that changes file permission modes.

Numeric permission 755

Permission mode representing rwx/r-x/r-x ($7=\text{rwx}$, $5=\text{r-x}$, $5=\text{r-x}$).

Numeric permission 644

Permission mode representing rw-/r--/r-- ($6=\text{rw-}$, $4=\text{r--}$, $4=\text{r--}$).

whoami

Command that displays and prints the effective username.

sudo

Command used for authorized elevated execution with delegated privileges.

top

Command that displays live, changing process activity.

apt

Package manager common on Debian and Ubuntu systems.

df -h

Command that reports filesystem disk space.