'Access denied' errors are due to restrictive permissions or ownership conflicts. Use chmod or chown to adjust permissions and access.

Access denied errors in Unix systems are typically permission-related, often due to ownership conflicts or restrictive file permissions. Begin by checking file permissions with ls -l, which lists permissions and ownership. Use chmod to adjust permissions; for example, chmod 755 filename grants read, write, and execute permissions to the owner, while only read and execute permissions to others. If ownership conflicts arise, use chown to change file ownership to your user. For sensitive files, ensure permissions comply with security standards; only grant write access when absolutely necessary. Ensure system-wide permissions changes align with your organization’s security policies. Scripts requiring permissions can specify them with sudo, though this requires careful management in collaborative environments. Testing permissions on non-critical files first reduces risk.