Linux Find ext2/ext3/ext4 filesystems Information Command

Fig.01: tune2fs command in action

Fig.01: tune2fs command in action

To see the contents of the filesystem superblock, including the current values of the parameters that can be set via this program, enter:
tune2fs -l /dev/sda5
tune2fs -l /dev/mapper/deviceName
tune2fs -l /dev/md0 | more

Sample outputs:

Filesystem volume name:   <none>
Last mounted on:          /
Filesystem UUID:          8b824e5c-6168-4442-ba47-504ee925aec2
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              7872512
Block count:              31464192
Reserved block count:     1573209
Free blocks:              29797103
Free inodes:              7749664
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1016
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
RAID stride:              128
RAID stripe width:        384
Flex block group size:    16
Filesystem created:       Sat Sep  3 00:49:43 2011
Last mount time:          Tue Oct 27 00:14:16 2015
Last write time:          Tue Oct 27 00:14:13 2015
Mount count:              18
Maximum mount count:      27
Last checked:             Sun Oct 18 23:38:28 2015
Check interval:           15552000 (6 months)
Next check after:         Fri Apr 15 23:38:28 2016
Lifetime writes:          90 GB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:	          256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
First orphan inode:       4063248
Default directory hash:   half_md4
Directory Hash Seed:      8b0bc481-33c5-4b84-b911-d0d6723c9fdf
Journal backup:           inode blocks

Examples and usage: How To See Characteristics of File Systems on Linux or Unix