Linux File, Permission, and Administrative Basics for A+
Short answer
- File operations: ls, pwd, mv, cp, rm are the basic filesystem commands. Understand where files are and how copying vs moving works. - Permissions and ownership: chmod adjusts permission bits; chown changes ownership. ls -l shows rwx bits and owner/group. - Searching and locating: grep searches file contents; find locates files by name, type, or other attributes. - Filesystem tools: fsck checks and repairs filesystem errors (use with care); mount attaches filesystems to mount points. - Admin access: su and sudo provide elevated privileges; prefer sudo for single-command elevation when configured.
Why it appears on the exam
- Given a permission error, pick the correct command sequence to check permissions and change them if appropriate. - Identify which command shows the current directory versus which lists contents. - Choose when to use sudo vs su based on a described support scenario.
Key concepts
Concept 1
Required terms
ls: Lists directory contents; common options show hidden files or long-format permissions. chmod: Changes file or directory permission bits (read/write/execute for owner/group/others). chown: Changes file owner and optionally group; requires appropriate privileges. su and sudo: su switches user identity (often to root); sudo runs a single command with elevated privileges as configured in sudoers.
Example
Show ls -la to reveal hidden files in a user's home directory.
Concept 2
How Linux File, Permission, and Administrative Basics works
- File operations: ls, pwd, mv, cp, rm are the basic filesystem commands. Understand where files are and how copying vs moving works. - Permissions and ownership: chmod adjusts permission bits; chown changes ownership. ls -l shows rwx bits and owner/group. - Searching and locating: grep searches file contents; find locates files by name, type, or other attributes. - Filesystem tools: fsck checks and repairs filesystem errors (use with care); mount attaches filesystems to mount points. - Admin access: su and sudo provide elevated privileges; prefer sudo for single-command elevation when configured.
Example
Use chmod to add execute permission for a script (chmod u+x script.sh).
Concept 3
Common confusion
- Confusing chmod and chown purposes. chmod = permissions; chown = ownership. - Running destructive commands as root unnecessarily; teach use of sudo and cautious commands. - Assuming rm is reversible; it is not without backups.
Example
Use sudo apt update (or a package manager) when a command requires elevated rights; use su
Concept 4
Core 2 (220-1202) question cues
Given a permission error, pick the correct command sequence to check permissions and change them if appropriate; Identify which command shows the current directory versus which lists contents; Choose when to use sudo vs su based on a described support scenario.
Example
when a full root environment is needed for maintenance.
Sample questions
Select an answer to reveal the explanation. For tracked practice and weak-area review, use the Cultiv8 app.
Q1.An A+ support scenario describes this situation: Show ls -la to reveal hidden files in a user's home directory. Which answer fits best?
Q2.A support ticket includes this clue: Use chmod to add execute permission for a script (chmod u+x script.sh). Which concept is being tested?
Q3.Read this A+ scenario: Use sudo apt update (or a package manager) when a command requires elevated rights; use su Which term or action matches it?
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