B4(5) File Formats Manual B4(5)
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 .
SUBCOMMANDS
Maintainer-oriented:
o mbox: Download a thread as an mbox file
o am: Create an mbox file that is ready to git-am
o shazam: Apply patch series to git repositories
o pr: Work with pull requests
o ty: Create templated replies for processed patches and pull requests
o diff: Show range-diff style diffs between patch versions
o kr: (STUB) Operate on patatt-compatible keyrings
Contributor-oriented:
o prep: prepare your series for submission
o trailers: retrieve and apply code-review trailers
o 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:
o pick the latest submitted version of the series (it can check for
newer threads using -c as well)
o check DKIM signatures and patatt attestation on all patches and code
review messages
o collate all submitted code-review trailers (Reviewed-by, Acked-by,
etc) and put them into the commit message
o add your own Signed-off-by trailer (with -s)
o reroll series from partial updates (e.g. someone submits a v2 of a
single patch instead of rerolling the entire series)
o guess where in the tree history the patches belong, if the exact
commit-base is not specified (with -g)
o prepare the tree for a 3-way merge (with -3)
o 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:
o it can check if the pull is already applied before performing a git
fetch
o it checks the signature on the tag or tip commit specified in the
pull request
o 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:
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
PROXYING REQUESTS
Commands making remote HTTP requests may be configured to use a proxy
by setting the HTTPS_PROXY environment variable, as described in
.
SUPPORT
Please email with support requests, or browse the
list archive at .
AUTHOR
mricon@kernel.org
License: GPLv2+
COPYRIGHT
The Linux Foundation and contributors
0.14.2 2024-06-14 B4(5)