df displays the amount of disk space available on the file system containing each file name argument. If no file name is given, the space available on all currently mounted file systems is shown. Read man page of df if you are new to df command. Steps => Find disk space using df => Filter [...]
NFS (Network File System) client allows you to access shared directory from Linux client. The computer sharing the directory is called the NFS server (it can be NAS server too) and the computers or devices connecting to that server are called clients. The clients need to use the mount command to access the shared directory.
You will never notice something like this on FreeBSD or Linux Desktop home system or your personal UNIX or Linux workstation. However, sometime on a production UNIX server you will notice that both df (display free disk space) and du (display disk usage statistics) reporting different output. Usually df will output a bigger disk usage [...]