File Permissions & Ownership

Summary

Linux's read/write/execute permission model for owner, group, and others — understanding chmod and chown is essential for both security and for debugging 'permission denied' errors constantly.

• 1Practice reading a permission string (e.g. rwxr-xr--) and translating it into plain English.
• 2Use chmod and chown to change permissions and ownership on test files.
• 3Learn the difference between numeric (755) and symbolic (u+x) chmod syntax.