d00d@computername:~/ $ diskutil list /dev/disk0 #: type name size identifier 0: GUID_partition_scheme *232.9 GB disk0 1: EFI 200.0 MB disk0s1 2: Apple_HFS Macintosh HD 232.6 GB disk0s2 /dev/disk1 #: type name size identifier 0: Apple_partition_scheme *931.5 GB disk1 1: Apple_partition_map 31.5 KB disk1s1 2: Apple_Driver43 28.0 KB disk1s2 3: Apple_Driver43 28.0 KB disk1s3 4: Apple_Driver_ATA 28.0 KB disk1s4 5: Apple_Driver_ATA 28.0 KB disk1s5 6: Apple_FWDriver 256.0 KB disk1s6 7: Apple_Driver_IOKit 256.0 KB disk1s7 8: Apple_Patches 256.0 KB disk1s8 9: Apple_HFS computername Backup 232.9 GB disk1s10 10: Apple_HFS My Book 648.4 GB disk1s12 11: Apple_HFS Stuff 49.9 GB disk1s14 d00d@computername:~/ $ diskutil --help Disk Utility Tool Utility to manage local disks and volumes. Most options require root access to the device Usage: diskutil is one of the following: list (List the partitions of a disk) information | info (Get information on a disk or volume) listRAID (List RAID masters and members) unmount (Unmount a single volume) unmountDisk (Unmount an entire disk (all volumes)) eject (Eject a disk) mount (Mount a single volume) mountDisk (Mount an entire disk (all mountable volumes)) rename (Rename a volume) enableJournal (Enable HFS+ journaling on a mounted HFS+ volume) disableJournal (Disable HFS+ journaling on a mounted HFS+ volume) verifyVolume (Verify the structure of a volume) repairVolume (Repair the structure of a volume) verifyPermissions (Verify the permissions of a volume) repairPermissions (Repair the permissions of a volume) repairOS9Permissions (Repair the permissions for the current Classic boot volume) eraseDisk (Erase an existing disk, removing all volumes) eraseVolume (Erase an existing volume) reformat (Reformat an existing volume) eraseOptical (Erase an optical media (CD/RW, DVD/RW, etc.)) zeroDisk (Erase a disk, writing zeros to the media) randomDisk (Erase a disk, writing random data to the media) secureErase (Securely erase a disk or freespace on a volume) resizeVolume (resize a volume, increasing or decreasing its size) partitionDisk ((re)Partition a disk, removing all volumes) createRAID (Create a RAID set on multiple disks) destroyRAID (Destroy an existing RAID set) checkRAID (Check a RAID set for errors) enableRAID (Convert a disk to a degraded RAID mirror set) convertRAID (Convert a RAID 1.x (pre-Tiger) to a RAID 2.x (Tiger)) updateRAID (Update the settings of an existing RAID) addToRAID (Add a spare or member disk to an existing RAID) removeFromRAID (Remove a spare or member disk from an existing RAID) repairMirror (Repair a damaged RAID mirror set) diskutil with no options will provide help on that verb d00d@computername:~/ $ diskutil resizeVolume Disk Utility Tool Usage: diskutil resizeVolume [Mount Point|Disk Identifier|Device Node] size ... Non-destructively resize a disk. You may increase or decrease its size. When decreasing size, you may optionally supply a list of new partitions to create. Ownership of the affected disk is required. Valid partition sizes are in the format of . Valid sizes are B(ytes), K(ilobytes), M(egabytes), G(igabytes), T(erabytes) Example: 10G (10 gigabytes), 4.23T (4.23 terabytes), 5M (5 megabytes) resizeVolume is only supported on GPT media with a Journaled HFS+ filesystem. A size of "limits" will print the range of valid values for the current filesystem. Example: diskutil resizeVolume disk1s3 10G JHFS+ HDX1 5G MS-DOS HDX2 5G Valid filesystems: "Ext2" "Case-sensitive HFS+" "Journaled HFS+" "Case-sensitive Journaled HFS+" "HFS+" "HFS" "MS-DOS FAT32" "MS-DOS FAT16" "MS-DOS" "MS-DOS FAT12" "UFS" "Linux" "Swap" d00d@computername:~/ $ diskutil limits Disk Utility Tool Utility to manage local disks and volumes. Most options require root access to the device Usage: diskutil is one of the following: list (List the partitions of a disk) information | info (Get information on a disk or volume) listRAID (List RAID masters and members) unmount (Unmount a single volume) unmountDisk (Unmount an entire disk (all volumes)) eject (Eject a disk) mount (Mount a single volume) mountDisk (Mount an entire disk (all mountable volumes)) rename (Rename a volume) enableJournal (Enable HFS+ journaling on a mounted HFS+ volume) disableJournal (Disable HFS+ journaling on a mounted HFS+ volume) verifyVolume (Verify the structure of a volume) repairVolume (Repair the structure of a volume) verifyPermissions (Verify the permissions of a volume) repairPermissions (Repair the permissions of a volume) repairOS9Permissions (Repair the permissions for the current Classic boot volume) eraseDisk (Erase an existing disk, removing all volumes) eraseVolume (Erase an existing volume) reformat (Reformat an existing volume) eraseOptical (Erase an optical media (CD/RW, DVD/RW, etc.)) zeroDisk (Erase a disk, writing zeros to the media) randomDisk (Erase a disk, writing random data to the media) secureErase (Securely erase a disk or freespace on a volume) resizeVolume (resize a volume, increasing or decreasing its size) partitionDisk ((re)Partition a disk, removing all volumes) createRAID (Create a RAID set on multiple disks) destroyRAID (Destroy an existing RAID set) checkRAID (Check a RAID set for errors) enableRAID (Convert a disk to a degraded RAID mirror set) convertRAID (Convert a RAID 1.x (pre-Tiger) to a RAID 2.x (Tiger)) updateRAID (Update the settings of an existing RAID) addToRAID (Add a spare or member disk to an existing RAID) removeFromRAID (Remove a spare or member disk from an existing RAID) repairMirror (Repair a damaged RAID mirror set) diskutil with no options will provide help on that verb d00d@computername:~/ $ diskutil resizeVolume Disk Utility Tool Usage: diskutil resizeVolume [Mount Point|Disk Identifier|Device Node] size ... Non-destructively resize a disk. You may increase or decrease its size. When decreasing size, you may optionally supply a list of new partitions to create. Ownership of the affected disk is required. Valid partition sizes are in the format of . Valid sizes are B(ytes), K(ilobytes), M(egabytes), G(igabytes), T(erabytes) Example: 10G (10 gigabytes), 4.23T (4.23 terabytes), 5M (5 megabytes) resizeVolume is only supported on GPT media with a Journaled HFS+ filesystem. A size of "limits" will print the range of valid values for the current filesystem. Example: diskutil resizeVolume disk1s3 10G JHFS+ HDX1 5G MS-DOS HDX2 5G Valid filesystems: "Ext2" "Case-sensitive HFS+" "Journaled HFS+" "Case-sensitive Journaled HFS+" "HFS+" "HFS" "MS-DOS FAT32" "MS-DOS FAT16" "MS-DOS" "MS-DOS FAT12" "UFS" "Linux" "Swap" d00d@computername:~/ $ diskutil resizeVolume /dev/disk0s2 limits For device disk0s2 Macintosh HD: Current size: 249715376128 bytes Minimum size: 228587577344 bytes Maximum size: 249715376128 bytes d00d@computername:~/ $ diskutil resizeVolume /dev/disk0s2 249715376127 249715376127 does not appear to be a valid disk size Disk Utility Tool Usage: diskutil resizeVolume [Mount Point|Disk Identifier|Device Node] size ... Non-destructively resize a disk. You may increase or decrease its size. When decreasing size, you may optionally supply a list of new partitions to create. Ownership of the affected disk is required. Valid partition sizes are in the format of . Valid sizes are B(ytes), K(ilobytes), M(egabytes), G(igabytes), T(erabytes) Example: 10G (10 gigabytes), 4.23T (4.23 terabytes), 5M (5 megabytes) resizeVolume is only supported on GPT media with a Journaled HFS+ filesystem. A size of "limits" will print the range of valid values for the current filesystem. Example: diskutil resizeVolume disk1s3 10G JHFS+ HDX1 5G MS-DOS HDX2 5G Valid filesystems: "Ext2" "Case-sensitive HFS+" "Journaled HFS+" "Case-sensitive Journaled HFS+" "HFS+" "HFS" "MS-DOS FAT32" "MS-DOS FAT16" "MS-DOS" "MS-DOS FAT12" "UFS" "Linux" "Swap" d00d@computername:~/ $ diskutil resizeVolume /dev/disk0s2 249715376127B Started resizing on disk disk0s2 Macintosh HD Verifying Resizing Volume Adjusting Partitions Formatting new partitions 100% .. Finished resizing on disk disk0 d00d@computername:~/ $ diskutil list /dev/disk0 #: type name size identifier 0: GUID_partition_scheme *232.9 GB disk0 /dev/disk1 #: type name size identifier 0: Apple_partition_scheme *931.5 GB disk1 1: Apple_partition_map 31.5 KB disk1s1 2: Apple_Driver43 28.0 KB disk1s2 3: Apple_Driver43 28.0 KB disk1s3 4: Apple_Driver_ATA 28.0 KB disk1s4 5: Apple_Driver_ATA 28.0 KB disk1s5 6: Apple_FWDriver 256.0 KB disk1s6 7: Apple_Driver_IOKit 256.0 KB disk1s7 8: Apple_Patches 256.0 KB disk1s8 9: Apple_HFS computername Backup 232.9 GB disk1s10 10: Apple_HFS My Book 648.4 GB disk1s12 11: Apple_HFS Stuff 49.9 GB disk1s14 /dev/disk2 #: type name size identifier 0: Apple_partition_scheme *7.5 GB disk2 1: Apple_partition_map 30.0 KB disk2s1 2: Apple_Driver_ATAPI 401.7 MB disk2s2 3: Apple_HFS Mac OS X Install DVD 7.1 GB disk2s3 d00d@computername:~/ $