Provided by: b4_0.14.2-2_all 
NAME
B4 - Work with code submissions in a public-inbox archive
SYNOPSIS
b4 {mbox,am,shazam,pr,diff,ty,kr,prep,send,trailers} [options]
DESCRIPTION
This is a helper utility to work with patches and pull requests made available via a public-inbox archive
like lore.kernel.org. It's written to make it simpler to participate in patch-based workflows, like those
used in the Linux kernel development.
The name "b4" was chosen for ease of typing and because B-4 was the precursor to Lore and Data in the
Star Trek universe.
Full documentation is available on https://b4.docs.kernel.org/.
SUBCOMMANDS
Maintainer-oriented:
• mbox: Download a thread as an mbox file
• am: Create an mbox file that is ready to git-am
• shazam: Apply patch series to git repositories
• pr: Work with pull requests
• ty: Create templated replies for processed patches and pull requests
• diff: Show range-diff style diffs between patch versions
• kr: (STUB) Operate on patatt-compatible keyrings
Contributor-oriented:
• prep: prepare your series for submission
• trailers: retrieve and apply code-review trailers
• send: send your series for review on distribution lists
For full options and what they do, please see b4 --help and b4 subcommand --help.
b4 mbox
This command allows retrieving entire threads from a remote public-inbox instance. You can open the
resulting mbox file with most mail clients for actions like replying to conversations or reviewing patch
submissions.
You can provide the message either as a msgid, as full URL to a public-inbox archive, or you can pipe it
on stdin.
For options and their descriptions, see b4 mbox --help.
Examples
b4 mbox [msgid]
Download a thread from the default public-inbox server and save it in the current directory as a
.mbox file.
b4 mbox -m ~/Mail [msgid]
Download a thread from your ~/Mail folder and save it in the current directlry as a .mbox file.
b4 mbox -fo ~/Mail [public-inbox-url]
Download the thread from this public-inbox server, and add it to your existing mailbox, filtering
out any dupes already in your mailbox folder.
b4 am
This command allows retrieving threads from a public-inbox instance and preparing them for applying to a
git repository using the "git am" command. It will automatically perform the following operations:
• pick the latest submitted version of the series (it can check for newer threads using -c as well)
• check DKIM signatures and patatt attestation on all patches and code review messages
• collate all submitted code-review trailers (Reviewed-by, Acked-by, etc) and put them into the commit
message
• add your own Signed-off-by trailer (with -s)
• reroll series from partial updates (e.g. someone submits a v2 of a single patch instead of rerolling
the entire series)
• guess where in the tree history the patches belong, if the exact commit-base is not specified (with -g)
• prepare the tree for a 3-way merge (with -3)
• cherry-pick a subset of patches from a large series (with -P)
Note: Unless you intend to do some preparatory work on the series before applying it to the git
repository (e.g. a 3-way merge), you should consider using b4 shazam to apply the retrieved series.
For options and their descriptions, see b4 am --help.
Examples
b4 am -sl [msgid]
Download a thread from the default public-inbox server, apply any follow-up trailers, add your own
Signed-Off-By trailer plus a Link: trailer indicating the origin of the patch, then save the
resulting .mbox file in the current directory ready to be applied by "git am".
b4 am -sl -P 1-3 [msgid]
Same as the previous example, but pick only patches 1,2,3 from the entire series.
b4 am -3 [msgid]
Download the series and prepare the local git tree for a 3-way merge by ensuring that all index
blobs exist.
b4 am --check [msgid]
Download the series and show if it passes the checks. You can specify the command using the
b4.am-perpatch-check-cmd configuration option. For the Linux kernel, the default will be the most
common checkpatch.pl set of options.
b4 shazam
This is very similar to b4 am, but will also apply patches directly to the current git tree using git am.
Alternatively, when used with -H, it can fetch the patch series into FETCH_HEAD as if it were a pull
request, ready to review and merge. B4 uses the cover letter as a template for the merge commit.
If you want to automatically invoke git-merge, you can use -M instead of -H. B4 automatically opens up
the editor allowing you to edit the merge commit message.
Note: the -M and -H options work best for series that have the base-commit info matching an object in
your local tree.
For options and their descriptions, see b4 shazam --help.
Examples
b4 shazam -sl -M [msgid]
Download a thread from the default public-inbox server, apply any follow-up trailers, add your own
Signed-Off-By trailer plus a Link: trailer with the origin of the patch, then merge this commit to
the current git repository using the cover letter as the merge commit template.
b4 shazam -sl -M --merge-base v6.4-rc4 [msgid]
Same as the previous example, but forces the merge-base to be the commit-ish object provided
instead of the one listed in the patch series itself.
b4 pr
This command is for working with pull requests submitted using git-request-pull. It provides the
following benefits as opposed to using git directly:
• it can check if the pull is already applied before performing a git fetch
• it checks the signature on the tag or tip commit specified in the pull request
• it can track applied pull requests and send replies to submitters using b4 ty
For options and their descriptions, see b4 pr --help.
Examples
b4 pr [msgid]
Download the message with the pull-request and apply it to the current git tree.
b4 ty
If you've retrieved and applied some patches to your tree, you should be able to fire up the
“auto-thankanator”, which uses patch-id and commit subject tracking to figure out which series from those
you have retrieved you already applied to your tree. The process is usually pretty fast and fairly
accurate.
To send mails directly using -S, you should have a configured [sendemail] section somewhere in your
applicable git configuration files. By default, b4 ty writes out .thanks files in the current directly
that you can edit and sent out using a command like mutt -f thanks.file.
For options and their descriptions, see b4 ty --help.
Examples
b4 ty -a -S
Locate any retrieved series that you have applied to the current git repository and send out
thanks to all members of the conversation.
b4 ty -a -S --dry-run
Same as above, but instead of actually sending it out show what the message is going to be, first.
b4 diff
The diff subcommand allows comparing two different revisions of the same patch series using git
range-diff. Note, that in order to perform the range-diff comparison, both revisions need to cleanly
apply to the current tree, which may not always be possible to achieve.
For options and their descriptions, see b4 diff --help.
Examples
b4 diff [msgid-of-vN]
Retrieves the thread matching the msgid specified and attempts to auto-locate the previous version
of the series. If successful, shows the output of git range-diff comparing the patch differences.
b4 kr
This subcommand allows maintaining a local keyring of contributor keys.
Note: this part of b4 is under active development with improvements planned for the near future.
For options and their descriptions, see b4 kr --help.
Examples
b4 kr --show-keys [msgid]
Retrieve the thread specified and show any cryptographic keys used to attest the patches.
b4 prep, trailers, send
These commands allow preparing and submitting a patch series for review on the mailing list. Full
documentation is available online at the following address:
https://b4.docs.kernel.org/en/latest/contributor/overview.html
For options, see the output of b4 prep --help, b4 trailers --help and b4 send --help.
Examples
b4 prep -n my-new-feature -f v6.4-rc4
Start a new branch, forking it from the tag v6.4-rc4, and prepare it for adding more patches.
b4 prep --edit-cover
Edit the cover letter for the current series. This step isn't required for most single-patch
submissions.
b4 prep --auto-to-cc
Find all addresses that need to receive a copy of the patch series submission and add them to the
cover letter.
b4 prep --check
Run the configured checks on your series to identify any potential problems. For Linux kernel,
this runs checkpatch.pl with the recommended set of parameters.
b4 send -o /tmp/outdir
Generate the patches that b4 is going to send out and save them into the directory specified. This
allows you to review the series before actually sending them.
b4 send --preview-to [addr1@example.com addr2@example.com]
Send a "preview" version of the series for someone to check before submitting it upstream.
b4 trailers -u
Retrieve any code-review trailers provided for your series and apply them to the current branch.
CONFIGURATION
B4 configuration is handled via git-config(1), so you can store it in either the toplevel
$HOME/.gitconfig file, or in a per-repository .git/config file if your workflow changes per project.
To see configuration options available, see online documentation at
https://b4.docs.kernel.org/en/latest/config.html
PROXYING REQUESTS
Commands making remote HTTP requests may be configured to use a proxy by setting the HTTPS_PROXY
environment variable, as described in https://docs.python-requests.org/en/latest/user/advanced/#proxies.
SUPPORT
Please email tools@kernel.org with support requests, or browse the list archive at
https://lore.kernel.org/tools.
AUTHOR
mricon@kernel.org
License: GPLv2+
COPYRIGHT
The Linux Foundation and contributors
0.14.2 2024-06-14 B4(5)