View source for get file system types

 $ '''lsblk -f'''
 NAME         FSTYPE      FSVER    LABEL UUID                                   FSAVAIL FSUSE% MOUNTPOINT
 sda                                                                                           
 ├─sda1       ext2        1.0            7ccd4a80-b6e0-4dc4-987b-57710e3c7b0a                  
 ├─sda2       swap        1              8654134a-12a4-4d93-a580-324c0d7b5ab0                  [SWAP]
 └─sda3       LVM2_member LVM2 001       jhlOlV-igV4-Xw0o-1GZr-2g1v-ZVn7-bUVRWO                
   ├─vg1-root ext4        1.0            78a8f0f0-4a8e-4b04-8649-1250d2ffa859     19.7G    37% /
   └─vg1-var  ext4        1.0            ef5306f7-2340-4926-97e2-f3ae3220a822     70.6G     7% /var