Practice with the format of `ls -l` and `chmod`

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When we type ls -l we get strings that correspond to the octal numbers used in chmod commands. For example:

This output in ls -l	could be set with this chmod command:
-rw-r--r--	chmod 644 filename
drwxr-xr-x	chmod 755 dirname
-rw-------	chmod 600 filename

The meanings are:

octal digit	binary equivalent	rwx format	meaning
0	000	`---`	no permission
1	001	`--x`	execute
2	010	`-w-`	write
3	011	`-wx`	write and execute
4	100	`r--`	read only
5	101	`r-x`	read and execute
6	110	`rw-`	read and write
7	111	`rwx`	read write and execute

The three digits in an octal number have different meanings depending on their positions (text borrowed from Wikipedia).

UGO = User, Group, Other
777 = "-rwxrwxrwx" = rwx for all
754 = "-rwxr-xr--" = rwx for owner of the file, r-x for group, r-- for other
124 = "---x-w-r--" = x for owner of the file, w for group, r for other

Quiz yourself!

This web page gives you an opportunity to practice with converting between the format used in ls -l output, and the octal numbers used in chmod.

We will ignore the first character in the ls -l output (which is a - for regular files, and a d for directories).

Each time you click the "make new quiz" button, you'll get a different randomly generated quiz.

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Practice with the format of ls -l and chmod

Quiz yourself!

Practice with the format of `ls -l` and `chmod`