chmod 100 Permission Explained
Summary: chmod 100 gives the owner execute, the group no access, and everyone else no access.
| Class | Read (4) | Write (2) | Execute (1) | Octal |
|---|---|---|---|---|
| Owner (u) | 1 | |||
| Group (g) | 0 | |||
| Others (o) | 0 |
chmod 100 filename
chmod 100 Breakdown
| Class | Digit | Symbolic | On a file | On a directory |
|---|---|---|---|---|
| Owner (u) | 1 |
--x |
Execute only | Can enter (cd) but not list contents |
| Group (g) | 0 |
--- |
No access | Cannot list, enter, or modify |
| Others (o) | 0 |
--- |
No access | Cannot list, enter, or modify |
Is chmod 100 Safe?
Restrictive
- Even the owner cannot modify this file without changing permissions first.
- Scripts need read permission to run; only compiled binaries can be executed without it.
Common Use Cases
100 is uncommon in standard Linux setups. The closest widely used permission is chmod 500.
chmod 100 Command Examples
# Apply using octal mode
chmod 100 filename
# Apply using equivalent symbolic mode
chmod u=x,g=,o= filename
# Recursive command warning:
chmod -R 100 /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 100 {} +
# Verify permissions
stat -c '%a %A %n' filename # Linux
stat -f '%Lp %Sp %N' filename # macOS
# Example ls -l output:
---x------ 1 alice staff 1024 Jan 15 10:00 example.txtumask Relationship
A umask of 677 makes new directories 100. Test umask values with our interactive Umask Calculator.
Frequently Asked Questions
What does chmod 100 mean?
chmod 100 gives the owner execute, the group no access, and everyone else no access. In octal notation, the owner receives 1 (execute), the group receives 0 (no access), and others receive 0 (no access).
Is chmod 100 safe?
chmod 100 is classified as Restrictive. Even the owner cannot modify this file without changing permissions first.
What is chmod 100 in symbolic notation?
In symbolic notation, chmod 100 is represented as --x------. You can apply this permission using the equivalent symbolic command "chmod u=x,g=,o= filename".
Related Permissions
Change one bit: