How to backup from Ubuntu bootable usb?

I have a problem when booting Ubuntu 19.10 on my laptop, I would just like to do a fresh install instead of solving the problem but before I do that there are a couple of important folders I need to backup. How do I do that with a Ubuntu bootable USB?

I created the USB and tried following a tutorial I found but I am at a loss of what to do. I clicked on "try Ubuntu" and then "files" then "other locations" then on what I think is my hard disk (called 496 GB volume, /dev/sda1) and when I click on it there's a series of folders.

How can I access my actual folders/files?

Please be patient, I am not good with this kind of stuff and desperate to recover some of my files. Thank you in advance for any help.

ubuntu@ubuntu:~$ lsblk -f

NAME FSTYPE LABEL UUID                                 FSAVAIL            FSUSE% MOUNTPOINT
loop0
 squash                                                  0   100% /rofs
loop1
 squash                                                  0   100% /snap/core
loop2
 squash                                                  0   100% /snap/gnom
loop3
 squash                                                  0   100% /snap/gtk-
loop4
 squash                                                  0   100% /snap/snap
loop5
 squash                                                  0   100% /snap/snap
sda                                                                   
├─sda1
│    ext4         557b262e-78a6-45b2-8b7d-78888556eef8    269G    36% /media/ubu
├─sda2
│                                                                     
└─sda5
 swap         98a60c88-d7e6-4e22-bc56-74d4f02a3552                [SWAP]
sdb  isw_ra                                                           
└─sdb1
                                                                  
sdc  iso966 Ubuntu 20.04.2.0 LTS amd64
│                 2021-02-09-19-06-26-00                              
├─sdc1
│    iso966 Ubuntu 20.04.2.0 LTS amd64
│                 2021-02-09-19-06-26-00                     0   100% /cdrom
├─sdc2
│    vfat         54C5-9C6C                                           
└─sdc3
 ext4   writable
              fc191471-2528-4a5c-a090-359ad18ffd0b     11G     0% /var/crash

ubuntu@ubuntu:~$ lsblk -m

NAME     SIZE OWNER GROUP MODE
loop0      2G root  disk  brw-rw----
loop1   55.5M root  disk  brw-rw----
loop2    219M root  disk  brw-rw----
loop3   64.8M root  disk  brw-rw----
loop4     51M root  disk  brw-rw----
loop5   31.1M root  disk  brw-rw----
sda    465.8G root  disk  brw-rw----
├─sda1 461.9G root  disk  brw-rw----
├─sda2     1K root  disk  brw-rw----
└─sda5   3.9G root  disk  brw-rw----
sdb     29.8G root  disk  brw-rw----
└─sdb1     4G root  disk  brw-rw----
sdc     14.6G root  disk  brw-rw----
├─sdc1   2.7G root  disk  brw-rw----
├─sdc2   3.9M root  disk  brw-rw----
└─sdc3  11.9G root  disk  brw-rw----

Solution 1:

Your data is always in /home/<your_username>, and you can copy from there to the usb drive.

Now, in your newly fresh install, instead of user your entire hard driver for one partition, I recommend to have at least three.

• on for / (root filesystem), 100G-120G size is more than enough
  
• on for swap (2 x ram size will work)
  
• on for /home (most of you data), rest of the disk if you want
  

when you tell ubuntu to create/change these partitions you alos specify if they need to be formated or not.

Now, in future reinstalls you won need to reformat your /home partition and just reuse it.

It is a also safe practice to write a log file with the changes you are doing to your system (in my case I have a bash shell script to restore the system to where I was left of so I can recover my system in an hour or so).

Let me know if this helps.

regards.