<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
How can I modify the size of a tmpfs filesystem?<|im_end|>
<|im_start|>assistant
To modify the size of a tmpfs filesystem on Linux, you can use the mount command with the -o (options) flag to adjust the 'size' option. Here are the steps to do that:

1. First, find out the current mounting point of your tmpfs filesystem using the df or mount command:
df -h

or
mount | grep tmpfs


Look for the line with 'tmpfs' in the output, and note down the mount point, such as /dev/shm or /tmp.

2. Unmount the tmpfs filesystem you want to resize, for example:
sudo umount /dev/shm


3. Mount the tmpfs filesystem with the new size. For instance, to set the size to 512MB, use:
sudo mount -t tmpfs -o size=512M tmpfs /dev/shm


Replace /dev/shm with the appropriate mount point and 512M with the desired size.

4. To make the change permanent, update the /etc/fstab file by adding or modifying the tmpfs entry with the new size:
tmpfs /dev/shm tmpfs defaults,size=512M 0 0


Ensure you replace /dev/shm and 512M with the relevant mount point and desired size, respectively. Save the changes and close the file.

5. Verify that the changes are successful with df -h:
df -h


The output should display the updated size for the specified tmpfs filesystem.<|im_end|>
<|im_start|>user
Thanks. That worked great!<|im_end|>
<|im_start|>assistant
I’m glad to have helped.<|im_end|>
<|im_start|>user
Thank you! Now tell me how to use debootstrap to create small Ubuntu 20.04 root filesystem.<|im_end|>
<|im_start|>assistant
Provided you have already installed debootstrap, you can use the following command to create a small [Ubuntu 20.04 (Focal Fossa)](https://releases.ubuntu.com/focal/) root file system for an amd64 compatible processor in the folder /mnt:

```debootstrap --variant=minbase --arch=amd64 focal /mnt http://archive.ubuntu.com/ubuntu```

You can find an in-depth explanation of all possible arguments in the [corresponding man page](https://manpages.ubuntu.com/manpages/trusty/man8/debootstrap.8.html).<|im_end|>