List Block Devices on FreeBSD lsblk(8) Style

When I have to work on Linux systems I usually miss many nice FreeBSD tools such as these for example to name the few:

  • sockstat
  • gstat
  • top -b -o res
  • top -m io -o total
  • usbconfig
  • rcorder
  • beadm/bectl
  • idprio/rtprio

… but sometimes – which rarely happens – Linux has some very useful tool that is not available on FreeBSD. An example of such tool is lsblk(8) that does one thing and does it quite well – lists block devices and their contents. It has some problems like listing a disk that is entirely used under ZFS pool on which lsblk(8) displays two partitions instead of information about ZFS just being there – but we all know how much in some circles the CDDL licensed ZFS is unloved in that GPL world.

Example lsblk(8) output from Linux system:

$ lsblk
NAME                         MAJ:MIN RM   SIZE RO TYPE   MOUNTPOINT
sr0                           11:0    1  1024M  0 rom
sda                            8:0    0 931.5G  0 disk
|-sda1                         8:1    0   500M  0 part   /boot
`-sda2                         8:2    0   931G  0 part
  |-vg_local-lv_root (dm-0)  253:0    0    50G  0 lvm    /
  |-vg_local-lv_swap (dm-1)  253:1    0  17.7G  0 lvm    [SWAP]
  `-vg_local-lv_home (dm-2)  253:2    0   1.8T  0 lvm    /home
sdc                            8:32   0 232.9G  0 disk
`-sdc1                         8:33   0 232.9G  0 part
  `-md1                        9:1    0 232.9G  0 raid10 /data
sdd                            8:48   0 232.9G  0 disk
`-sdd1                         8:49   0 232.9G  0 part
  `-md1                        9:1    0 232.9G  0 raid10 /data

What FreeBSD offers in this department? The camcontrol(8) and geom(8) commands are available. You can also use gpart(8) command to list partitions. Below you will find output of these commands from my single disk laptop. Please note that because of WordPress limitations I need to change all > < characters to ] [ ones in the commands outputs.

# camcontrol devlist
[Samsung SSD 860 EVO mSATA 1TB RVT41B6Q]  at scbus1 target 0 lun 0 (ada0,pass0)

% geom disk list
Geom name: ada0
1. Name: ada0
   Mediasize: 1000204886016 (932G)
   Sectorsize: 512
   Mode: r1w1e2
   descr: Samsung SSD 860 EVO mSATA 1TB
   lunid: 5002538e402b4ddd
   ident: S41PNB0K303632D
   rotationrate: 0
   fwsectors: 63
   fwheads: 1

# gpart show
=>        40  1953525088  ada0  GPT  (932G)
          40      409600     1  efi  (200M)
      409640        1024     2  freebsd-boot  (512K)
      410664         984        - free -  (492K)
      411648  1953112064     3  freebsd-zfs  (931G)
  1953523712        1416        - free -  (708K)

They provide needed information in acceptable manner but only on systems with small amount of disks. What if you would like to display a summary of all system drives contents? This is where comes handy. While lsblk(8) has many interesting features like --perms/--scsi/--inverse modes I focused to provide only the basic feature – to list the system block devices and their contents. As I have long and pleasing experience with writing shell scripts such as sysutils/beadm or sysutils/automount I though that writing may be a good idea. I actually ‘open-sourced’ or should I say shared that project/idea in 2016 in this thread lsblk(8) Command for FreeBSD on FreeBSD Forums but lack of time really slowed that ‘side project’ development pace. I finally got back to it to finish it.

The is generally small and simple shell script which tales less then 400 SLOC.


Here is example output of command from my single disk laptop.

DEVICE         MAJ:MIN  SIZE TYPE                      LABEL MOUNT
ada0             0:5b  932G GPT                           - -
  ada0p1         0:64  200M efi                    efiboot0 [UNMOUNTED]
  ada0p2         0:65  512K freebsd-boot           gptboot0 -
  [FREE]         -:-   492K -                             - -
  ada0p3         0:66  931G freebsd-zfs                zfs0 [ZFS]
  [FREE]         -:-   708K -                             - -

Same output in graphical window.


Below you will find an example output from server with two system SSD drives (da0/da1) and two HDD data drives (da2/da3).

DEVICE         MAJ:MIN SIZE TYPE                      LABEL MOUNT
da0              0:be  224G GPT                           - -
  da0p1          0:15a 200M efi                    efiboot0 [UNMOUNTED]
  da0p2          0:15b 512K freebsd-boot           gptboot0 -
  [FREE]         -:-   492K -                             - -
  da0p3          0:15c 2.0G freebsd-swap              swap0 [UNMOUNTED]
  da0p4          0:15d 221G freebsd-zfs                zfs0 [ZFS]
  [FREE]         -:-   580K -                             - -
da1              0:bf  224G GPT                           - -
  da1p1          0:16a 200M efi                    efiboot1 [UNMOUNTED]
  da1p2          0:16b 512K freebsd-boot           gptboot1 -
  [FREE]         -:-   492K -                             - -
  da1p3          0:16c 2.0G freebsd-swap              swap1 [UNMOUNTED]
  da1p4          0:16d 221G freebsd-zfs                zfs1 [ZFS]
  [FREE]         -:-   580K -                             - -
da2              0:c0   11T GPT                           - -
  da2p1          0:16e  11T freebsd-zfs                   - [ZFS]
  [FREE]         -:-   1.0G -                             - -
da3              0:c1   11T GPT                           - -
  da3p1          0:16f  11T freebsd-zfs                   - [ZFS]
  [FREE]         -:-   1.0G -                             - -

Below you will find other examples from other systems I have tested on.


While is not the fastest script on Earth (because of all the needed parsing) it does its job quite well. If you would like to install it in your system just type the command below:

# fetch -o /usr/local/bin/lsblk
# chmod +x /usr/local/bin/lsblk
# hash -r || rehash
# lsblk

If I got time which other original Linux lsblk(8) subcommand/option/argument is worth adding to the script? πŸ™‚


UPDATE 1 – Added USAGE/HELP Information

Just added some usage information that can be displayed by specifying one of these as argument:

  • h
  • -h
  • --h
  • help
  • -help
  • --help

IMHO writing man page for such simple utility is needless. I think I will create dedicated man page when tool will grow in size and options to comparable with the Linux lsblk(8) equivalent. Here is how it looks.

# --help

  # [DISK]


  DEVICE         MAJ:MIN SIZE TYPE                      LABEL MOUNT
  ada0             0:5b  932G GPT                           - -
    ada0p1         0:64  200M efi                    efiboot0 [UNMOUNTED]
    ada0p2         0:65  512K freebsd-boot           gptboot0 -
    [FREE]         -:-   492K -                             - -
    ada0p3         0:66  931G freebsd-zfs                zfs0 [ZFS]

  # da1
  DEVICE         MAJ:MIN SIZE TYPE                      LABEL MOUNT
  da1              0:80  2.0G MBR                           - -
    da1s1          0:80  2.0G freebsd                       - -
      da1s1a       0:81  1.0G freebsd-ufs                root /
      da1s1b       0:82  1.0G freebsd-swap               swap SWAP


  # sysctl kern.disks
  kern.disks: ada0 da0 da1


UPDATE 2 – Code Reorganization and 75% Rewrite

… at least this is what git(1) tries to tell me after commit message.

% git commit (...)
[master 12fd4aa] Rework entire flow. Split code into functions. Add many useful comments. In other words its 2.0 version.
 1 file changed, 494 insertions(+), 505 deletions(-)
 rewrite (75%)

After several productive hours new incarnation of is now available.

It has similar SLOC but its now smaller by a quarter … while doing more and with better accuracy. Great example why “less is more.”

% wc scripts/
     491    2201   19721 scripts/

% wc scripts/
     494    1871   15472 scripts/

Things that does not have simple solution are described below.

One of them is ‘double’ label for FAT filesystems. We have both /dev/gpt/efiboot0 label and FAT label is named EFISYS. We have to choose something here. As not all FAT filesystems have label I have chosen the GPT label.

% glabel status | grep ada0p1
  gpt/efiboot0     N/A  ada0p1
msdosfs/EFISYS     N/A  ada0p1

I was also not able to cover FUSE mounts. When you mount – for example – the /dev/da0 device as NTFS (with ntfs-3g) or exFAT (with mount.exfat) there is no visible difference in mount(8) output.

% mount -t fusefs
/dev/fuse on /mnt/ntfs (fusefs)
/dev/fuse on /mnt/exfat (fusefs)

When I mount such filesystem by my daemon (like sysutils/automount) I keep track of what device have been mounted to which directory in the /var/run/automount.state file. Then when I get the detach event for /dev/da0 device I know what to u(n)mount … but when I only have /dev/fuse device its just not possible.

… or maybe YOU know any way of extracting information from /dev/fuse (or generally from FUSE) what device is mounted where?

Now little presentation after update.

Here are various non ZFS filesystems mounted.

% mount -t nozfs
devfs on /dev (devfs, local, multilabel)
linprocfs on /compat/linux/proc (linprocfs, local)
tmpfs on /compat/linux/dev/shm (tmpfs, local)
/dev/label/ASD on /mnt/tmp (msdosfs, local)
/dev/fuse on /mnt/ntfs (fusefs)
/dev/md0s1f on /mnt/ufs.other (ufs, local)
/dev/gpt/OTHER on /mnt/fat.other (msdosfs, local)
/dev/md0s1a on /mnt/ufs (ufs, local)

… and here is how now displays them.

DEVICE         MAJ:MIN SIZE TYPE                      LABEL MOUNT
ada0             0:56  932G GPT                           - -
  ada0p1         0:64  200M efi                gpt/efiboot0 -
  ada0p2         0:65  512K freebsd-boot       gpt/gptboot0 -
  [FREE]         -:-   492K -                             - -
  ada0p3         0:66  931G freebsd-zfs                   - [ZFS]
  [FREE]         -:-   708K -                             - -
md0              0:28f 1.0G MBR                           - -
  md0s1          0:294 512M freebsd                       - -
    md0s1a       0:29a 100M freebsd-ufs                root /mnt/ufs
    md0s1b       0:29b  32M freebsd-swap         label/swap SWAP
    md0s1e       0:29c  64M freebsd-ufs                   - -
    md0s1f       0:29d 316M freebsd-ufs                   - /mnt/ufs.other
  md0s2          0:296 256M ntfs                          - -
  md0s3          0:297 256M fat32               msdosfs/ONE -
md1              0:2a4 1.0G msdosfs                   LARGE 
md2              0:298 2.0G GPT                           - -
  md2p1          0:29f 2.0G ms-basic-data         gpt/OTHER /mnt/fat.other

I used some file based memory devices for this. Now by default also displays memory disks contents.

% -l
md0     vnode    1024M  /home/vermaden/FILE     
md2     vnode    2048M  /home/vermaden/FILE.GPT 
md1     vnode    1024M  /home/vermaden/FILER    

Here is how it looks in the xterm(1) terminal.



UPDATE 3 – Added geli(8) Support

I thought that adding geli(8) support may be useful. The latest now avoids code duplication for MOUNT and LABEL detection (moved into single unified function). Also added more comments for code readability and some minor fixes … and its again smaller πŸ™‚

% wc
     491    2201   19721

% wc
     493    1861   15415

% wc
     488    1820   15332

About 40% (according to git commit was changed this time (191 insertions and 196 deletions).

# git commit (...)
[master ec9985a] Add geli(8) support. Avoid code duplication and move MOUNT/LABEL detection into function. More comments. Minor fixes.
 1 file changed, 191 insertions(+), 196 deletions(-)

Also forgot to mention that now thanks to smart optimizations (like not doing things twice and aggregating grep(1) | awk(1) pipes into single awk(1) queries) runs 3 times faster then the initial version πŸ™‚

New output with geli(8) support below.



UPDATE 4 – Added fuse(8) Support

As I wrote in the UPDATE 2 keeping track of what is mounted and where under fuse(8) is very hard as all mounted devices magically become /dev/fuse after mount is done.

After little research I found that this information (what really is mounted where by using fuse(8) interface under FreeBSD) is available after mounting procfs filesystem under /proc. You just need to cat cmdline entry for all PIDs of ntfs-3g. Its not perfect but the information at least is available.

# mount -t procfs proc /proc

# ps ax | grep ntfs-3g
45995  -  Is      0:00.00 ntfs-3g /dev/md1s2 /mnt/ntfs
59607  -  Is      0:00.00 ntfs-3g /dev/md3 /mnt/ntfs.another
83323  -  Is      0:00.00 ntfs-3g /dev/md3 /mnt/ntfs.another

# pgrep ntfs-3g

% pgrep ntfs-3g | while read I; do cat /proc/$I/cmdline; echo; done

This was the code prototype that worked for fuse(8) mountpoints detection.

    if [ -e /proc/0/status ]
        while read PID
          cat /proc/${PID}/cmdline
        done << ________EOF
          $( pgrep ntfs-3g )
      FUSE_MOUNTS=$( echo "${FUSE_MOUNTS}" | sort -u )
      FUSE_MOUNTS=$( echo "${FUSE_MOUNTS}" | sed 's|ntfs-3g||g' )
      FUSE_CHECKS=$( echo "${FUSE_MOUNTS}" | grep /dev/${TARGET}/ )
      if [ "${FUSE_CHECKS}" != "" ]
        MOUNT=$( echo "${FUSE_CHECKS}" | sed "s|/dev/${TARGET}||g" )

… and I have just realized that I found new (better) way of getting that information without mounting /proc filesystem – all you need to do is to display the ntfs-3g processes with their command line arguments, for example like that:

% ps -p $( pgrep ntfs-3g | tr '\n' ',' | sed '$s/.$//' ) -o command | sed 1d
ntfs-3g /dev/md1s2 /mnt/ntfs
ntfs-3g /dev/md3 /mnt/ntfs.another
ntfs-3g /dev/md3 /mnt/ntfs.another

So after I also thought that its only for NTFS (ntfs-3g(8) process) I also added exFAT support by searching for mount.exfat PIDs as well. The fuse(8) mount point detection works now for both NTFS and exFAT filesystems … and code to support it is even shorter.

  if [ "${MOUNT_FOUND}" != "1" ]
    FUSE_PIDS=$( pgrep mount.exfat ntfs-3g | tr '\n' ',' | sed '$s/.$//' )
    FUSE_MOUNTS=$( ps -p "${FUSE_PIDS}" -o command | sed 1d | sort -u )
    MOUNT=$( echo "${FUSE_MOUNTS}" |  grep "/dev/${TARGET} " | awk '{print $3}' )

I also changed how MAJOR and MINOR numbers are displayed – from HEX to DEC – as it is on Linux. The FreeBSD’s ls(1) from Base System displays these as HEX – for example you will get 0x2af value:

% ls -l /dev/md4
crw-rw----  1 root  operator  0x2af 2019.09.29 05:18 /dev/md4

But do the same with GNU equivalent by using gls(1) from FreeBSD Ports (from sysutils/coreutils package) and it shows MAJOR and MINOR in DEC values. The gls(1) is just ls(1) from the Linux world but as ls(1) name is already ‘taken’ by FreeBSD’s Base System tool the FreeBSD developers/maintainers add ‘g’ letter (for GNU) to distinguish them.

% gls -l /dev/md4
crw-rw---- 1 root 2, 175 2019-09-29 05:18 /dev/md4

… and they are also easier/faster to get with stat(1) tool.

  MAJ=$( stat -f "%Hr" /dev/${DEV} )
  MIN=$( stat -f "%Lr" /dev/${DEV} )

Latest looks like that now.


… that is why I did not (yet) added to the FreeBSD Ports. Several new versions with important features span across just two days πŸ™‚


UPDATE 5 – Another 69% Rewrite

After messing with gpart(8) more I found that using its -p flag which is a game changer. The difference is that with -p flag it displays names along partitions – its no longer needed to find the PREFIX and ‘create’ partition names.

Default gpart(8) output.

# gpart show md0
=>     63  2097089  md0  MBR  (1.0G)
       63  1048576    1  freebsd  (512M)
  1048639   524288    2  ntfs  (256M)
  1572927   524225    3  fat32  (256M)

Output of gpart(8) with -p flag.

# gpart show -p md0
=>     63  2097089    md0  MBR  (1.0G)
       63  1048576  md0s1  freebsd  (512M)
  1048639   524288  md0s2  ntfs  (256M)
  1572927   524225  md0s3  fat32  (256M)

That discovery implicated a quite large rewrite of The git commit estimates this as 69% code rewrite.

# git commit (...)
 1 file changed, 487 insertions(+), 501 deletions(-)
 rewrite (69%)

The latest has now these features:

  • Previous bugs fixed.
  • Detects exFAT labels.
  • Is now 20% faster.
  • Has less 10% SLOC.
  • Has less 15% of code.
  • Handles bsdlabel(8) on entire device properly.
  • Handles exFAT on entire device properly.

The difference in code is shown below.

# wc
     487    1791   13705

# wc
     544    1931   16170

Latest looks as usual but I now use ‘-‘ instead of ‘[UNMOUNTED]‘ one.


UPDATE 6 – New Updated and Fixed Version

The has been updated to 3.4 version – also already updated in the FreeBSD Ports tree – in the sysutils/lsblk port.
The Changelog for this version is below:
  • Add sysctl -n kern.disks to disk listing.
  • Reset LABEL in __gpart_present function.
  • Fix behavior with [bootme] and [bootonce] flags from gpart(8).
  • Disable GPTID for label display.
  • Add -d|–disks option to list entire disks only.
Keep in mind that uses diskinfo(8) which – to function properly – need you to be in the operator group. You can add yourself to that group like that:
# pw groupmod operator -m yourself

… or by editing the /etc/group file.

Here is example output.


UPDATE 7 – More Fixes

The has been updated to 3.5 version – also already updated in the FreeBSD Ports tree – in the sysutils/lsblk port.
The Changelog for this version is below:
  • Remove control sequences and colors from output when listing disks.
  • Use diskinfo(8) only for md(4) disks as geom(4) does not support them.
  • Add new comments and rework some of the older ones.
  • Add additional checks for SIZE gathering and printing.
  • Properly print exFAT filesystem label when on entire device without partitions.
  • Fix display of NTFS-3G mountpoints.
  • Check automount(8) /var/run/automount.state for fusefs(5) filesystems.
Presence in the operator group is only needed for size for md(4)disks. All other disks size is gathered using geom(8)command now.

13 thoughts on “List Block Devices on FreeBSD lsblk(8) Style

  1. Pingback: In Other BSDs for 2019/09/28 – DragonFly BSD Digest

  2. Alexej Magura

    Why not use the double bracket builtin `[[` for conditional tests instead of `[`, which maps to `test`? Also do you have a github or gitlab where contributions can be made to this and your other programs/projects?


    1. vermaden Post author

      Hi, thank you for comment.

      I use [ because [ is POSIX. The [[ is not POSIX – thus I am not interested. All my scripts must work under plain POSIX /bin/sh – that is my requirement for scripts.

      About the GitHub page – sure – here they are:

      The is here:



  3. Le Zap

    Quite nice! Can I suggest adding a simple “–version” flag to the script to let us know which version of the script we are running?


    1. vermaden Post author

      It does support that πŸ™‚

      % lsblk --version
        ___     ___   ___ __       _ _ _____    
        \  \  __\__\__\  \  \  __ / / /     \   
         \  \/  __/    \  \  \/ // / /   .   \  
          \  \___ \  \  \  \_   \\ \ \    \  / 
      lsblk 3.1 2020/09/03


  4. georg

    Good script, but I encountered a problem on my Thinkpad X1. My internal disk were not displayed, because it is a nvd device.
    May be you should use the result of ‘sysctl -n kern.disks’ for building your list of disks.



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