File permissions·764
764
rwxrw-r--
-rwxrw-r--

chmod 764 — the rwxrw-r-- permission

764 is rwxrw-r--. The owner gets rwx, and everyone else gets r.

Who can do what

Three rows for owner, group and others; three columns for read, write and execute. On a folder that last one means the right to go inside.

ReadWriteExecute
Owner7
Group6·
Others4··

On a folder the execute bit means going inside. With read but no execute you can list the names yet open nothing in it.

Symbolic
rwxrw-r--
ls -l (file)
-rwxrw-r--
ls -l (directory)
drwxrw-r--
chmod symbolic form
chmod u=rwx,g=rw,o=r
Command
chmod 764 <file>
Binary
111110100
Decimal
500
umask (directory)
013
umask (file)
Not reachable — new files never start with the execute bit

One digit away

How to read this

  • Read is 4, write 2, execute 1; add them for one digit. 7 is 4+2+1, 5 is 4+1.
  • The digits are owner, group, others, left to right.
  • umask is what gets taken away: from 777 for directories, from 666 for files.
  • Special bits (setuid 4000, setgid 2000, sticky 1000) add a fourth digit in front — /tmp is 1777.

Frequently asked questions

Q. What does chmod 764 mean?

It is rwxrw-r--. ls -l shows a file as -rwxrw-r-- and a directory as drwxrw-r--.

Q. How is 764 written in rwx form?

It is the same as chmod u=rwx,g=rw,o=r.

Q. What can other people do with 764?

They get r--.

Q. Which umask produces 764?

013 for directories. For files it cannot be reached by umask alone, since new files never carry the execute bit.