Question $3$c:

Linux file system permissions use $3$ octal $($digits $0-7)$ nibbles $($each octal nibble is $3$ bits$)$ to

define permissions for, respectively, the resource$$s $($file or directory$))$ owner, the resource$$s

group owner, and finally the rest of the universe. The first bit denotes whether the resource

is a directory $($d$)$ or a file $(-)($or other type of filesystem node$).$ The next nine bits are

defined in this order: read $($r$),$ write $($w$),$ execute $($x$).$ A dash is used to show that the

permission is set to false.

The ls command lists the contents of a directory, but there are flags that can give ad$-$

ditional information besides the file and directory names. The command ls $-$alh will list

all the contents of a directory $($including hidden files and folders$),$ will give the long form

$($including permissions information and when it was last edited$),$ and will do so in human

readable form. The output of ls $-$l has the following values: