[English] Debian Almquist Shell (dash) umask Usage: Set default file permissions

Overview

The umask command in the Debian Almquist Shell (dash) is used to set the default file permissions for newly created files and directories. It defines the permissions that will not be set when a new file or directory is created, effectively controlling the default access rights.

Usage

The basic syntax of the umask command is as follows:

umask [options] [arguments]

Common Options

-S: Display the current umask in symbolic format.
-p: Display the current umask value in a way that can be reused in a script.

Common Examples

Check Current Umask Value To see the current umask value:
```
umask
```
Set Umask Value To set the umask to 022, which allows read and execute permissions for others but not write:
```
umask 022
```
Set Umask in Symbolic Format To set the umask using symbolic notation, which removes write permissions for group and others:
```
umask u=rwx,g=rx,o=rx
```
Display Current Umask in Symbolic Format To display the current umask in a more readable format:
```
umask -S
```
Persisting Umask Changes To make the umask change permanent for a user, add the umask command to the user’s shell profile file (e.g., ~/.profile):
```
echo 'umask 027' >> ~/.profile
```

Tips

Always check the current umask before creating files or directories to ensure they have the desired permissions.
Use symbolic notation for easier readability when setting umask values.
Remember that the umask value is subtracted from the default permissions; for example, a default permission of 666 for files minus a umask of 022 results in 644 permissions for new files.