Toggle read / write / execute for owner, group, and others and this instantly shows
the numeric mode (like 755), the symbolic
form, and the exact chmod command to copy. No more memorizing
the number table.
Numeric mode–
Symbolic form–
Owner / Group / Others–
Command (file)–
Command (directory, recursive)–
Special bits (setuid 4, setgid 2, sticky 1)
can be prepended, e.g. 4755 for setuid – rarely needed for normal use.