resize2fs
Resize an ext2, ext3, or ext4 filesystem. tldr-pages
On Linux
Linux
Resize an ext2, ext3, or ext4 filesystem. Does not resize the underlying partition. The filesystem may have to be unmounted first, read the man page for more details.
Automatically resize a filesystem to its maximum possible size
resize2fs /dev/sdXNIdentifyResize the filesystem to a size of 40G, displaying a progress bar
resize2fs -p /dev/sdXN 40GIdentifyShrink the filesystem to its minimum possible size
resize2fs -M /dev/sdXNIdentify