Df

df displays free disk space on each mounted volume. The tool displays the file system, total size, amount used and available, this information as a percentage, and the mount point.

Using the -h flag lists amounts in human-readable terms of "K" for kilobytes, "M" for megabytes and "G" for gigabytes, instead of numbers of blocks.

Example
$ df -h Filesystem           Size  Used Avail Use% Mounted on /dev/hda2              74G   34G   41G  46% / /dev/hdc1            150G   44G  106G  29% /bulk shmfs                 94M     0   94M   0% /dev/shm

= Provided by =

Most (all?) Linux distributions incorporate this from the GNU Coreutils: man page

= Related Commands =
 * du - Report disk usage by directory
 * lsblk
 * mount
 * stat - Report status from an inode
 * sync - Update all cached disk blocks.
 * truncate - Change file length