By default, when you create a file as a regular user, it’s given the permissions of **rw-rw-r–**. You can use the //umask// (stands for **user mask**) command to determine the default permissions for newly created files.

The** umask** is the value that is subtracted from the **666** (**rw-rw-rw-**) permissions when creating new files, or from **777** (**rwxrwxrwx**) when creating new directories. For example, if the default umask is **002**, new files will be created with the **664** (**rw-rw-r–**) permissions, and new directories with the **775** (**rwxrwxr-x**) permissions.

To dispay the current value of **umask**, run the //umask// command without any options:

Ignore the first zero for now. The last three numbers represent the default **umask value**.

To temporarily change your **umask** value, run the// umask// //VALUE// command. This changes the umask value only for the current shell:

In the picture above you can see that we have changed the **umask** value to** 044**. Remember the numbers representing the permissions: **r**=**4**, **w**=**2** and **x**=**1**. The umask of **044** means that the permissions for the newly created files will be **rw- -w- -w-** or** 622** (because **044** subtracted from **666** gives** 622**). The permissions for the newly created directories will be **rwx -wx -wx** or** 733** (because **044** subtracted from **777** gives **733**).

By default, execute permissions are off for regular files.

To change the default umask value permanently for a specific user, you need to modify the **.bashrc** file in the user’s home directory. For example, to change the default umask for user** bob**, just add the following line at the end of the **/home/bob/.bashrc** file:

Reopen the shell. The default umask value is now **044**:

To change the default umask value permanently for all users, you can use the following command:

pam-config -a –umask –umask-umask=VALUE

Replace the last three numbers with the umask of your choice. The change will be made the next time you log in to the system. Note that the umask definition in the **.bashrc** file will override the system umask.

https://geek-university.com/set-the-default-permissions-for-newly-created-files/