To add a temporary directory entry to
/etc/fstab, first create the mount point directory (e.g., /mnt/temp), then add a tmpfs line to /etc/fstab with the mount options defaults,nosuid,nodev,noatime and a 0 0 at the end. A complete line would look like: tmpfs /mnt/temp tmpfs defaults,nosuid,nodev,noatime 0 0.
Step 1: Create the temporary directory
Create the directory where you want to mount the temporary file system. It's common to use a location like /mnt/temp or /media/temp for this purpose.
bash

sudo mkdir /mnt/temp

Step 2: Edit /etc/fstab
Open the /etc/fstab file using a text editor with root privileges. nano is a common and user-friendly choice.
bash

sudo nano /etc/fstab

Step 3: Add the entry
Go to the end of the file and add a new line for the temporary directory.

   tmpfs: Specifies that the file system is a temporary file system, which is stored in RAM.
   /mnt/temp: The mount point you created in the previous step.
   tmpfs: The file system type.
   defaults,nosuid,nodev,noatime: The mount options.
       defaults: Uses default mount options for a temporary RAM disk.
       nosuid: Prevents set-user-ID and set-group-ID bits from taking effect.
       nodev: Prevents device files from being interpreted.
       noatime: Prevents the access time of files from being updated.
   0 0: The dump and fsck pass numbers. A value of 0 for both means they are not used.

Full entry:

tmpfs /mnt/temp tmpfs defaults,nosuid,nodev,noatime 0 0

Step 4: Save and exit
Save the file and exit the editor. For nano, press Ctrl+X, then Y, and then Enter.
Step 5: Apply the changes
To mount the new file system without rebooting, run the following command:
bash

sudo mount -a