#zfs #backup #restore #cli-utility #snapshot

app httm

A CLI tool for viewing snapshot file versions on ZFS and btrfs datasets

133 releases (16 breaking)

new 0.32.3 Dec 3, 2023
0.31.7 Nov 28, 2023
0.30.0 Jul 6, 2023
0.25.5 Mar 30, 2023
0.14.7 Jul 30, 2022

#30 in Operating systems

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MPL-2.0 license

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Rust 6.5K SLoC // 0.1% comments BASH 713 SLoC // 0.2% comments Shell 53 SLoC // 0.1% comments Zsh 51 SLoC // 0.3% comments



The dream of a CLI Time Machine is still alive with httm.

httm prints the size, date and corresponding locations of available unique versions (deduplicated by modify time and size) of files residing on snapshots, but can also be used interactively to select and restore files, even snapshot mounts by file! httm might change the way you use snapshots (because ZFS/BTRFS/NILFS2 aren't designed for finding for unique file versions) or the Time Machine concept (because httm is very fast!).

httm boasts an array of seductive features, like:

  • Search for versions of multiple files on distinct datasets simultaneously
  • Search for and recursively list deleted files. Even browse files hidden behind deleted directories.
  • List file snapshots from all local pools (detect local snapshot versions as well as locally replicated snapshot versions)!
  • List file snapshots from remote backup pools (even overlay replicated remote snapshot directories over live directories).
  • For use with rsync-ed non-ZFS/BTRFS/NILFS2 local datasets (like ext4, APFS, or NTFS), not just ZFS/BTRFS/NILFS2.
  • Optionally preview snapshot file versions with a custom command (default is a diff compare to the live version)
  • List or even snapshot the mounts for a file directly
  • Roll forward to a previous snapshots, instead of rolling back (avoids destroying interstitial snapshots)
  • Guard any restore actions with precautionary snapshots
  • List snapshot names, even prune snapshots, which include a file name
  • Shortcut features: only display last snapshot, omit duplicates of the live file, etc.
  • Uniqueness level: Like rsync, httm can determine whether file is unique based solely on metadata, or use checksums
  • 4 native interactive modes: browse, select, prune and restore
  • ANSI ls colors from your environment
  • Detect and display only categories of the numbers of unique file versions available (multiple, single, single-with-snap,..., etc.)
  • Select from several formatting styles (newline, null, tab delimited, JSON, etc.). Parseable ... or not ... oh my!
  • Packaged scripts which help you, and show you how to, use httm: ounce, bowie, and nicotine
  • Supports ZFS/BTRFS/NILFS2 snapshots

Use in combination with you favorite shell's hot keys for even more fun.

Inspired by the findoid script, fzf and many zsh key bindings.

Install via Native Packages

For Debian-based distributions (like Ubuntu), I maintain an (unsupported) personal package archive, or PPA. See the linked repository.

For Debian-based and Redhat-based Linux distributions (like Ubuntu or Fedora, etc.), also check the tagged releases for native packages for your distribution. For Redhat-based Linux distributions, you may need to use the --replacefiles option when installing via rpm -i, see the linked issue.

You may also create and install your own native package from the latest sources, for Debian-based and Redhat-based Linux distributions, like so:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
cargo install cargo-deb 
git clone https://github.com/kimono-koans/httm.git
cd ./httm/; cargo deb
# to install on a Debian/Ubuntu-based system
dpkg -i ./target/debian/httm_*.deb
# or convert to RPM 
alien -r ./target/debian/httm_*.deb
# and install on a Redhat-based system
rpm -i --replacefiles ./httm_*.rpm

For Arch-based Linux distributions, you can create and install your own native package from the latest sources, like so:

# you need to edit the PKGBUILD as needed to conform to the latest release
wget https://raw.githubusercontent.com/kimono-koans/httm/master/packaging/arch/PKGBUILD
makepkg -si

For MacOS users, a user from the community (very exciting) has posted a formulae for Homebrew.

Install via Source

The httm project contains only a few components:

  1. The httm executable. To build and install:

    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
    latest="(wget -nv -O - "https://api.github.com/repos/kimono-koans/httm/releases/latest" 2>/dev/null | grep tag_name | cut -d: -f2 | cut -d'"' -f2)"
    cargo install --git https://github.com/kimono-koans/httm.git --tag "$latest"
  2. The optional zsh hot-key bindings: Use ESC+s to select snapshots filenames to be dropped to your command line (for instance after the cat command), or use ESC+m to browse for all of a file's snapshots. After you install the httm binary, to copy the hot key script to your home directory, and source that script within your .zshrc:

    httm --install-zsh-hot-keys
  3. The optional man page: cargo has no native facilities for man page installation (though it may in the future!). You can use manpath to see the various directories your system uses and decide which directory works best for you. To install, just copy it to a directory in your man path, like so:

    cp ./httm/httm.1 /usr/local/share/man/man1/
  4. The optional scripts. See script usage below, in the Example Usage section, or follow the links (ounce, bowie, and nicotine), for more information. To install, just copy it to a directory in your path, like so:

    cp ./httm/scripts/ounce.bash /usr/local/bin/ounce
    cp ./httm/scripts/bowie.bash /usr/local/bin/bowie
    cp ./httm/scripts/nicotine.bash /usr/local/bin/nicotine
    chmod +x /usr/local/bin/bowie /usr/local/bin/ounce /usr/local/bin/nicotine


Right now, you will probably need to use a Unix-ish-y Rust-supported platform to build and install (that is: only Linux, FreeBSD, and MacOS are known to work). Note, your platform does not need to support ZFS/BTRFS/NILFS2 to use httm. And there is no fundamental reason a non-interactive Windows version of httm could not be built, as it once did build, but Windows platform support is not a priority for me right now. Contributions from users are, of course, very welcome.

On FreeBSD, after a fresh minimal install, the interactive modes may not render properly, see the linked issue for the fix.

On some Linux distributions, which include old versions of libc, cargo may require building with musl instead, see the linked issue.

Example Usage

Note: Users may need to use sudo (or equivalent) to view versions on BTRFS or NILFS2 datasets, as BTRFS or NILFS2 snapshots may require root permissions in order to be visible.

Like other UNIX utilities (such as cat, uniq, sort), if you include no path/s as arguments, then httm will pause waiting for input on stdin:

# Press CTRL+C to send a SIGINT and quit the program
➜ httm 
# Pipe output of find command to httm
➜ find . -maxdepth 1 | httm

Print all unique versions of your history file:

 httm ~/.histfile

Print all unique versions of your history file, as formatted JSON:

 httm --json ~/.histfile

Print all files on snapshots deleted from your home directory, recursive:

 httm -d -R ~

Print all files on snapshots deleted from your home directory, recursive, newline delimited, piped to a text file:

# pseudo live file versions
➜ httm -d -n -R --no-snap ~ > pseudo-live-versions.txt
# unique snapshot versions
➜ httm -d -n -R --no-live ~ > deleted-unique-versions.txt

Browse all files in your home directory, recursively, and view unique versions on local snapshots:

 httm -b -R ~

Browse all files deleted from your home directory, recursively, and view unique versions on all local and alternative replicated dataset snapshots:

 httm -d=only -b -a -R ~

Browse all files in your home directory, recursively, and view unique versions on local snapshots, to select and ultimately restore to your working directory:

 httm -r -R ~

View unique versions of a file for recovery (shortcut, no need to browse a directory):

 httm -r /var/log/samba/log.smbd

httm also seeks to be a good Unix citizen, which means -- you should use the other Unix utilities to organize your queries how you like them. find and awk are especially useful here:

# search for the text "pattern" among snapshots of httm manpage
➜ httm -n --omit-ditto /usr/share/man/man1/httm.1.gz | xargs rg "pattern" -z

# print all unique versions of your `/var/log/syslog` file, 
# newline delimited piped to `find` to print only versions 
# with modify times of less than 1 day from right now.
➜ httm -n --omit-ditto /var/log/syslog | xargs -I{} find '{}' -mtime -1

# httm usually sorts snapshot versions in chronological order, 
# oldest to newest, but since these are just paths/strings 
# you may choose to sort them differently.
# here, print all unique versions of your `/var/log/syslog` file, 
# then print each snapshot version's size in bytes first, 
# then reverse sort by its size, then remove the number of bytes, 
# leaving only the paths in their new sorted order
➜ httm -n --omit-ditto /var/log/syslog | xargs -I{} find '{}' -printf '%s\t%p\n' | \
sort -rn | awk 'BEGIN {FS="\t"}; {print $2}'

View bowie-formatted diff of each unique snapshot of ~/.zshrc against the live file version:

 httm --preview -s ~/.zshrc

View cat output of each unique snapshot of ~/.zshrc:

 httm --preview="cat {snap_file}" -s ~/.zshrc

Recover the last-in-time unique file version (shortcut, no need to browse a directory or select from among other unique versions):

 httm -l -r /var/log/samba/log.smbd

Snapshot the dataset upon which /etc/samba/smb.conf is located:

 sudo httm -S /etc/samba/smb.conf

Browse all files, recursively, in a folder backed up via rsync to a remote share, and view unique versions on remote snapshots directly (only available for BTRFS Snapper and ZFS datasets).

# mount the share
➜ open smb://<your name>@<your remote share>.local/Home
# execute httm
➜ httm -b -R /Volumes/Home

Browse all files, recursively, in your MacOS home directory backed up via rsync to a ZFS or BTRFS Snapper remote share, shared via smbd, and view unique versions on remote snapshots. Note: The difference from above is, here, you're browsing files from a "live" directory:

# mount the share
➜ open smb://<your name>@<your remote share>.local/Home
# execute httm
➜ httm -b -R --map-aliases /Users/<your name>:/Volumes/Home ~

View the differences between each unique snapshot version of the httm man page and each previous version (this simple script is the basis for bowie):

# previous version is unset
for current_version in $(httm -n --omit-ditto $filename); do
    # check if initial "previous_version" needs to be set
    if [[ -z "$previous_version" ]]; then

    # print that current version and previous version differ
    diff -q "$previous_version" "$current_version"
    # print the difference between that current version and previous_version
    diff "$previous_version" "$current_version"

    # set current_version to previous_version

Create a simple tar archive of all unique versions of your /var/log/syslog:

 httm -n --omit-ditto /var/log/syslog | tar -zcvf all-versions-syslog.tar.gz -T -

Create a kinda fancy tar archive of all unique versions of your /var/log/syslog:

dir_name="${$(dirname $file)/\//}"
base_dir="$(basename $file)_all_versions"
# squash extra directories by "transforming" them to simply snapshot names 
httm -n --omit-ditto "$file" | \
tar \
--transform="flags=r;s|$dir_name|$base_dir|" \
--transform="flags=r;s|.zfs/snapshot/||" \
--show-transformed-names \
-zcvf "all-versions-$(basename $file).tar.gz" -T  -

Create a super fancy git archive of all unique versions of /var/log/syslog (this simple script is the basis for nicotine):

# create variable for file name
# create git repo
mkdir ./archive-git; cd ./archive-git; git init
# copy each version to repo and commit after each copy
for version in $(httm -n --omit-ditto $file); do
    cp "$version" ./
    git add "./$(basename $version)"
    # modify commit date to match snapshot modify date-time
    git commit -m "httm commit from ZFS snapshot" \
    --date "$(date -d "$(stat -c %y $version)")"
# create git tar.gz archive
tar -zcvf "../all-versions-$(basename $file).tar.gz" "./"
# and to view
git log --stat

Use ounce (codename: "dimebag"), a wrapper script for httm, for no mental overhead, non-periodic dynamic snapshots:

# request ZFS snapshot privileges
➜ ounce --give-priv
# here you create a "dummyfile", ounce will add a snapshot of "dummyfile" 
# before you remove it, and httm will allow you to view the snapshot created
➜ touch ~/dummyfile; ounce rm ~/dummyfile; httm ~/dummyfile
Wed Feb 15 12:59:42 2023  0 bytes  "/home/kimono/.zfs/snapshot/snap_2023-02-15-12:59:42_ounceSnapFileMount/dummyfile"
# use as an alias around programs which modify files/dirs
➜ printf "
# ounce aliases 
alias vim=\"ounce --trace vim\"
alias emacs=\"ounce --trace emacs\"
alias nano=\"ounce --trace nano\"
alias rm=\"ounce rm\"" >> ~/.zsh_aliases

Use bowie, a wrapper script for httm, to display the difference between unique snapshot versions and the live file:

 bowie ~/.zshrc
Files /home/kimono/.zfs/snapshot/snap_2023-02-14-13:42:11_ounceSnapFileMount/.zshrc and /home/kimono/.zshrc differ
< ### If you come from bash you might have to change your $PATH.
> # If you come from bash you might have to change your $PATH.

Use nicotine, a wrapper script for httm, to convert unique snapshot file versions to git archives:

 nicotine .zshrc
nicotine git archive created successfully: /home/kimono/zshrc-git.tar.gz

Roll forward to a previous ZFS snapshot, instead of rolling back (this avoids destroying interstitial snapshots):

 sudo httm --roll-forward=rpool/scratch@snap_2023-04-01-15:26:06_httmSnapFileMount
[sudo] password for kimono:
httm took a pre-execution snapshot named: rpool/scratch@snap_pre_2023-04-01-15:27:38_httmSnapRollForward
httm roll forward completed successfully.
httm took a post-execution snapshot named: rpool/scratch@snap_post_2023-04-01-15:28:40_:snap_2023-04-01-15:26:06_httmSnapFileMount:_httmSnapRollForward

Yo, @kimono-koans, where do your snapshots come from?

If you'd like to read more about how someone else/I personally create snapshots, you might try my A Somewhat Opinionated Guide to Effective ZFS Snapshots.

I know what you're thinking, but slow your roll

To be clear, httm is not...


httm is licensed under the MPL 2.0 License - see the LICENSE file for more details.


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