Master Linux Disk Monitoring: df, pydf, fdisk & sfdisk Commands Explained

df command

The df utility reports file‑system disk usage. Using the -hT options displays size, used space, available space, usage percentage, file‑system type, and mount point in a human‑readable format.

[root@localhost ~]# df -hT
Filesystem              Type      Size  Used Avail Use% Mounted on
devtmpfs                devtmpfs  898M     0  898M   0% /dev
tmpfs                   tmpfs     910M     0  910M   0% /dev/shm
tmpfs                   tmpfs     910M   29M  881M   4% /run
tmpfs                   tmpfs     910M     0  910M   0% /sys/fs/cgroup
/dev/mapper/centos-root xfs        37G  1.6G   36G   5% /
/dev/sda1               xfs      1014M  150M  865M  15% /boot
tmpfs                   tmpfs     182M     0  182M   0% /run/user/0

pydf command

pydf is a Python‑based alternative to df that adds colour‑coded output. It is not included by default in CentOS 7/RHEL 7; install it via pip (or apt on Ubuntu).

# Install pip on CentOS/RHEL
[root@localhost ~]# yum -y install python-pip
# Upgrade pip
[root@localhost ~]# pip install --upgrade pip
# Install pydf
[root@localhost ~]# pip install pydf

On Ubuntu: $ sudo apt install pydf Display all file systems:

[root@localhost ~]# pydf -a

Show usage in a human‑readable format:

[root@localhost ~]# pydf -h
Filesystem        Size  Used Avail Use%                          Mounted on
/dev/centos/root   37G 1624M   35G  4.3 [#.....................] /         
/dev/sda1        1014M  149M  865M 14.7 [###...................] /boot

fdisk command

fdisk is a classic Linux utility for partition management. The -l option lists all partitions and their device names.

[root@localhost ~]# fdisk -l

To view details of a specific disk, supply the device name after -l (e.g., fdisk -l /dev/sda).

sfdisk command

sfdisk offers scriptable partitioning similar to fdisk but can display sizes in megabytes using the -uM option.

[root@localhost ~]# sfdisk -l -uM