chmod 1755 Permission Explained: Sticky Bit Without World-Write
Summary: The sticky bit has little effect here.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 7 | |||
| Group (g) | 5 | |||
| Others (o) | 5 |
chmod 1755 filename
chmod 1755 Breakdown
| Class | Digit | Symbolic | On a file | On a directory |
|---|---|---|---|---|
| Owner (u) | 7 |
rwx |
Full access | Full access: list, enter, create, delete |
| Group (g) | 5 |
r-x |
Read and execute | Can list and enter |
| Others (o) | 5 |
r-x |
Read and execute | Can list and enter |
| Special | 1 |
— | sticky bit (restricted deletion) | |
Is chmod 1755 Safe?
Low Risk
- Any user can read this file — never use it for secrets such as keys or .env files.
When not to use it
- Directories where multi-user file deletion protection is actually needed
Common Use Cases
- Rare historical setups; mostly referenced in Unix systems administration exams
- Directories where world-write was intentionally stripped to restrict file creation
chmod 1755 Command Examples
# Apply using octal mode
chmod 1755 filename
# Apply using equivalent symbolic mode
chmod u=rwx,g=rx,o=rx,+t filename
# Recursive command warning:
chmod -R 1755 /path/to/dir
# Note: -R applies the same mode to files and directories. Use find to treat them separately:
find /path/to/dir -type d -exec chmod 1755 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
-rwxr-xr-t 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 022 makes new directories 1755. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 1755 mean?
The sticky bit has little effect here. In octal notation, the owner receives 7 (read/write/execute), the group receives 5 (read/execute), and others receive 5 (read/execute).
Is chmod 1755 safe?
chmod 1755 is classified as Low Risk. Any user can read this file — never use it for secrets such as keys or .env files.
What is chmod 1755 in symbolic notation?
In symbolic notation, chmod 1755 is represented as rwxr-xr-t. You can apply this permission using the equivalent symbolic command "chmod u=rwx,g=rx,o=rx,+t filename".
When does the sticky bit matter?
The sticky bit primarily matters on world-writable directories (mode 1777 like /tmp). Without the sticky bit, any user on a system could delete files created by other users in a shared folder. On files, the historical sticky bit used to keep program text in swap space, but modern Linux kernels ignore it entirely on regular files.
Related Permissions
Change one bit: