554
r-xr-xr--
-r-xr-xr--
chmod 554 — the r-xr-xr-- permission
554 is r-xr-xr--. The owner gets rx, 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.
| Read | Write | Execute | |
|---|---|---|---|
| Owner5 | ✓ | · | ✓ |
| Group5 | ✓ | · | ✓ |
| 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
- r-xr-xr--
- ls -l (file)
- -r-xr-xr--
- ls -l (directory)
- dr-xr-xr--
- chmod symbolic form
- chmod u=rx,g=rx,o=r
- Command
- chmod 554 <file>
- Binary
- 101101100
- Decimal
- 364
- umask (directory)
- 223
- 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 554 mean?
It is r-xr-xr--. ls -l shows a file as -r-xr-xr-- and a directory as dr-xr-xr--.
Q. How is 554 written in rwx form?
It is the same as chmod u=rx,g=rx,o=r.
Q. What can other people do with 554?
They get r--.
Q. Which umask produces 554?
223 for directories. For files it cannot be reached by umask alone, since new files never carry the execute bit.