04. Setting Default Permissions umask

When we create a file or directory, accession modes are applied by default. We can see and change these defaults with umask.

Default settings

To look at your current masking simply use the umask command.

$ umask
0022

Since our umask is set to 0022, and the default file mode is usually 666, we have:

Original file mode
- rw- rw- rw-
Masking
- --- -1- -1-
Result
- rw- r-- r--

Thus we see the canonical 644 file permission that we get when we create new files.

$ touch sampleFile.txt
$ ls -l sampleFile.txt
-rw-r--r-- 1 JohnDoe staff 0 Mar 30 18:34 sampleFile.txt

Changing umask

To change umask, simply pass the octal value as an argument (include a 0 for the file mode).

$ umask 0777
$ touch sampleFile2.txt
$ ls -l sampleFile2.txt
---------- 1 JohnDoe staff 0 Apr 01 18:34 sampleFile2.txt

Here, we would cannot do anything with our sampleFile2.txt because umask suppressed all its accession modes.

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