Calculate Linux/Unix file permissions numerically (755, 644) and symbolic notation (rwxr-xr-x) with interactive checkboxes.
755 grants Read, Write, and Execute to the owner, and Read + Execute to group and others.
Usually 644 for regular files (rw-r--r--) and 755 for directories.
Read = 4, Write = 2, Execute = 1. Add them together for each user category.