FM / git

/usr/share/doc/git

Name	Size	Mode	Actions
contrib/	-	0755	rm
howto/	-	0755	rm
RelNotes/	-	0755	rm
technical/	-	0755	rm
blame-options.txt	6001	0644	edit dl rm
cmds-ancillaryinterrogators.txt	1294	0644	edit dl rm
cmds-ancillarymanipulators.txt	746	0644	edit dl rm
cmds-developerinterfaces.txt	678	0644	edit dl rm
cmds-foreignscminterface.txt	399	0644	edit dl rm
cmds-guide.txt	833	0644	edit dl rm
cmds-mainporcelain.txt	3033	0644	edit dl rm
cmds-plumbinginterrogators.txt	1539	0644	edit dl rm
cmds-plumbingmanipulators.txt	1410	0644	edit dl rm
cmds-purehelpers.txt	1268	0644	edit dl rm
cmds-synchelpers.txt	449	0644	edit dl rm
cmds-synchingrepositories.txt	397	0644	edit dl rm
cmds-userinterfaces.txt	507	0644	edit dl rm
CODE_OF_CONDUCT.md	5989	0644	edit dl rm
config.txt	18001	0644	edit dl rm
date-formats.txt	1172	0644	edit dl rm
diff-format.txt	6573	0644	edit dl rm
diff-generate-patch.txt	7253	0644	edit dl rm
diff-options.txt	32436	0644	edit dl rm
docbook-xsl.css	4557	0644	edit dl rm
everyday.html	16996	0644	edit dl rm
fetch-options.txt	12281	0644	edit dl rm
fsck-msgids.txt	4197	0644	edit dl rm
git-add.html	40369	0644	edit dl rm
git-add.txt	16164	0644	edit dl rm
git-am.html	33161	0644	edit dl rm
git-am.txt	9317	0644	edit dl rm
git-annotate.html	28391	0644	edit dl rm
git-annotate.txt	771	0644	edit dl rm
git-apply.html	33407	0644	edit dl rm
git-apply.txt	10950	0644	edit dl rm
git-archive.html	29856	0644	edit dl rm
git-archive.txt	8491	0644	edit dl rm
git-bisect-lk2009.html	81243	0644	edit dl rm
git-bisect-lk2009.txt	49694	0644	edit dl rm
git-bisect.html	40572	0644	edit dl rm
git-bisect.txt	17905	0644	edit dl rm
git-blame.html	42501	0644	edit dl rm
git-blame.txt	8732	0644	edit dl rm
git-branch.html	48253	0644	edit dl rm
git-branch.txt	15748	0644	edit dl rm
git-bugreport.html	20509	0644	edit dl rm
git-bugreport.txt	2421	0644	edit dl rm
git-bundle.html	33269	0644	edit dl rm
git-bundle.txt	11703	0644	edit dl rm
git-cat-file.html	38661	0644	edit dl rm
git-cat-file.txt	13615	0644	edit dl rm
git-check-attr.html	22633	0644	edit dl rm
git-check-attr.txt	3390	0644	edit dl rm
git-check-ignore.html	23135	0644	edit dl rm
git-check-ignore.txt	4156	0644	edit dl rm
git-check-mailmap.html	18816	0644	edit dl rm
git-check-mailmap.txt	1108	0644	edit dl rm
git-check-ref-format.html	24040	0644	edit dl rm
git-check-ref-format.txt	5034	0644	edit dl rm
git-checkout-index.html	25362	0644	edit dl rm
git-checkout-index.txt	5669	0644	edit dl rm
git-checkout.html	52719	0644	edit dl rm
git-checkout.txt	22362	0644	edit dl rm
git-cherry-pick.html	31065	0644	edit dl rm
git-cherry-pick.txt	8764	0644	edit dl rm
git-cherry.html	22423	0644	edit dl rm
git-cherry.txt	3615	0644	edit dl rm
git-clean.html	23981	0644	edit dl rm
git-clean.txt	4523	0644	edit dl rm
git-clone.html	44328	0644	edit dl rm
git-clone.txt	14772	0644	edit dl rm
git-column.html	23317	0644	edit dl rm
git-column.txt	2201	0644	edit dl rm
git-commit-graph.html	26147	0644	edit dl rm
git-commit-graph.txt	5949	0644	edit dl rm
git-commit-tree.html	26683	0644	edit dl rm
git-commit-tree.txt	2710	0644	edit dl rm
git-commit.html	57154	0644	edit dl rm
git-commit.txt	21575	0644	edit dl rm
git-config.html	415540	0644	edit dl rm
git-config.txt	19755	0644	edit dl rm
git-contacts.html	20718	0644	edit dl rm
git-contacts.txt	2584	0644	edit dl rm
git-count-objects.html	18946	0644	edit dl rm
git-count-objects.txt	1350	0644	edit dl rm
git-credential-cache--daemon.html	18182	0644	edit dl rm
git-credential-cache--daemon.txt	891	0644	edit dl rm
git-credential-cache.html	20180	0644	edit dl rm
git-credential-cache.txt	2484	0644	edit dl rm
git-credential-store.html	22043	0644	edit dl rm
git-credential-store.txt	3637	0644	edit dl rm
git-credential.html	26676	0644	edit dl rm
git-credential.txt	7327	0644	edit dl rm
git-describe.html	28268	0644	edit dl rm
git-describe.txt	8319	0644	edit dl rm
git-diagnose.html	20157	0644	edit dl rm
git-diagnose.txt	2208	0644	edit dl rm
git-diff-files.html	79130	0644	edit dl rm
git-diff-files.txt	1225	0644	edit dl rm
git-diff-index.html	84351	0644	edit dl rm
git-diff-index.txt	4811	0644	edit dl rm
git-diff-tree.html	116052	0644	edit dl rm
git-diff-tree.txt	4184	0644	edit dl rm
git-diff.html	107093	0644	edit dl rm
git-diff.txt	8039	0644	edit dl rm
git-difftool.html	27048	0644	edit dl rm
git-difftool.txt	4624	0644	edit dl rm
git-fast-export.html	31650	0644	edit dl rm
git-fast-export.txt	11282	0644	edit dl rm
git-fast-import.html	103283	0644	edit dl rm
git-fast-import.txt	59963	0644	edit dl rm
git-fetch-pack.html	23255	0644	edit dl rm
git-fetch-pack.txt	4248	0644	edit dl rm
git-fetch.html	75456	0644	edit dl rm
git-fetch.txt	11812	0644	edit dl rm
git-filter-branch.html	54648	0644	edit dl rm
git-filter-branch.txt	31031	0644	edit dl rm
git-fmt-merge-msg.html	21435	0644	edit dl rm
git-fmt-merge-msg.txt	1931	0644	edit dl rm
git-for-each-ref.html	43438	0644	edit dl rm
git-for-each-ref.txt	17073	0644	edit dl rm
git-for-each-repo.html	19296	0644	edit dl rm
git-for-each-repo.txt	1543	0644	edit dl rm
git-format-patch.html	81842	0644	edit dl rm
git-format-patch.txt	28876	0644	edit dl rm
git-fsck-objects.html	17392	0644	edit dl rm
git-fsck-objects.txt	354	0644	edit dl rm
git-fsck.html	39162	0644	edit dl rm
git-fsck.txt	5882	0644	edit dl rm
git-fsmonitor--daemon.html	22875	0644	edit dl rm
git-fsmonitor--daemon.txt	3610	0644	edit dl rm
git-gc.html	36697	0644	edit dl rm
git-gc.txt	6292	0644	edit dl rm
git-get-tar-commit-id.html	17835	0644	edit dl rm
git-get-tar-commit-id.txt	753	0644	edit dl rm
git-grep.html	36030	0644	edit dl rm
git-grep.txt	10763	0644	edit dl rm
git-hash-object.html	19939	0644	edit dl rm
git-hash-object.txt	2142	0644	edit dl rm
git-help.html	28141	0644	edit dl rm
git-help.txt	7527	0644	edit dl rm
git-hook.html	18807	0644	edit dl rm
git-hook.txt	1028	0644	edit dl rm
git-http-backend.html	30974	0644	edit dl rm
git-http-backend.txt	11472	0644	edit dl rm
git-http-fetch.html	19679	0644	edit dl rm
git-http-fetch.txt	1775	0644	edit dl rm
git-http-push.html	21391	0644	edit dl rm
git-http-push.txt	2995	0644	edit dl rm
git-imap-send.html	25472	0644	edit dl rm
git-imap-send.txt	3567	0644	edit dl rm
git-index-pack.html	24735	0644	edit dl rm
git-index-pack.txt	5205	0644	edit dl rm
git-init-db.html	17460	0644	edit dl rm
git-init-db.txt	409	0644	edit dl rm
git-init.html	26604	0644	edit dl rm
git-init.txt	5869	0644	edit dl rm
git-interpret-trailers.html	42006	0644	edit dl rm
git-interpret-trailers.txt	18579	0644	edit dl rm
git-log.html	182485	0644	edit dl rm
git-log.txt	6864	0644	edit dl rm
git-ls-files.html	35053	0644	edit dl rm
git-ls-files.txt	11622	0644	edit dl rm
git-ls-remote.html	24349	0644	edit dl rm
git-ls-remote.txt	4841	0644	edit dl rm
git-ls-tree.html	25628	0644	edit dl rm
git-ls-tree.txt	5515	0644	edit dl rm
git-mailinfo.html	23402	0644	edit dl rm
git-mailinfo.txt	3866	0644	edit dl rm
git-mailsplit.html	19264	0644	edit dl rm
git-mailsplit.txt	1342	0644	edit dl rm
git-maintenance.html	46000	0644	edit dl rm
git-maintenance.txt	18901	0644	edit dl rm
git-merge-base.html	28380	0644	edit dl rm
git-merge-base.txt	7759	0644	edit dl rm
git-merge-file.html	22656	0644	edit dl rm
git-merge-file.txt	3718	0644	edit dl rm
git-merge-index.html	20450	0644	edit dl rm
git-merge-index.txt	2445	0644	edit dl rm
git-merge-one-file.html	17416	0644	edit dl rm
git-merge-one-file.txt	387	0644	edit dl rm
git-merge-tree.html	33496	0644	edit dl rm
git-merge-tree.txt	11923	0644	edit dl rm
git-merge.html	71005	0644	edit dl rm
git-merge.txt	15068	0644	edit dl rm
git-mergetool--lib.html	19127	0644	edit dl rm
git-mergetool--lib.txt	1467	0644	edit dl rm
git-mergetool.html	39795	0644	edit dl rm
git-mergetool.txt	4473	0644	edit dl rm
git-mktag.html	19819	0644	edit dl rm
git-mktag.txt	1782	0644	edit dl rm
git-mktree.html	18474	0644	edit dl rm
git-mktree.txt	1075	0644	edit dl rm
git-multi-pack-index.html	23595	0644	edit dl rm
git-multi-pack-index.txt	4632	0644	edit dl rm
git-mv.html	20092	0644	edit dl rm
git-mv.txt	2103	0644	edit dl rm
git-name-rev.html	21670	0644	edit dl rm
git-name-rev.txt	3352	0644	edit dl rm
git-notes.html	41046	0644	edit dl rm
git-notes.txt	13866	0644	edit dl rm
git-pack-objects.html	42391	0644	edit dl rm
git-pack-objects.txt	19297	0644	edit dl rm
git-pack-redundant.html	19799	0644	edit dl rm
git-pack-redundant.txt	1876	0644	edit dl rm
git-pack-refs.html	21120	0644	edit dl rm
git-pack-refs.txt	3136	0644	edit dl rm
git-patch-id.html	20354	0644	edit dl rm
git-patch-id.txt	2430	0644	edit dl rm
git-prune-packed.html	18539	0644	edit dl rm
git-prune-packed.txt	946	0644	edit dl rm
git-prune.html	20327	0644	edit dl rm
git-prune.txt	1919	0644	edit dl rm
git-pull.html	77070	0644	edit dl rm
git-pull.txt	8354	0644	edit dl rm
git-push.html	74993	0644	edit dl rm
git-push.txt	28061	0644	edit dl rm
git-quiltimport.html	19466	0644	edit dl rm
git-quiltimport.txt	1693	0644	edit dl rm
git-range-diff.html	31673	0644	edit dl rm
git-range-diff.txt	10337	0644	edit dl rm
git-read-tree.html	39078	0644	edit dl rm
git-read-tree.txt	16897	0644	edit dl rm
git-rebase.html	98945	0644	edit dl rm
git-rebase.txt	47228	0644	edit dl rm
git-receive-pack.html	30448	0644	edit dl rm
git-receive-pack.txt	9526	0644	edit dl rm
git-reflog.html	23514	0644	edit dl rm
git-reflog.txt	4575	0644	edit dl rm
git-remote-ext.html	23012	0644	edit dl rm
git-remote-ext.txt	3977	0644	edit dl rm
git-remote-fd.html	19501	0644	edit dl rm
git-remote-fd.txt	1628	0644	edit dl rm
git-remote-helpers.html	16974	0644	edit dl rm
git-remote.html	29903	0644	edit dl rm
git-remote.txt	8768	0644	edit dl rm
git-repack.html	32819	0644	edit dl rm
git-repack.txt	11020	0644	edit dl rm
git-replace.html	24858	0644	edit dl rm
git-replace.txt	5211	0644	edit dl rm
git-request-pull.html	20295	0644	edit dl rm
git-request-pull.txt	2035	0644	edit dl rm
git-rerere.html	27040	0644	edit dl rm
git-rerere.txt	7781	0644	edit dl rm
git-reset.html	44520	0644	edit dl rm
git-reset.txt	19125	0644	edit dl rm
git-restore.html	28166	0644	edit dl rm
git-restore.txt	7082	0644	edit dl rm
git-rev-list.html	118128	0644	edit dl rm
git-rev-list.txt	3220	0644	edit dl rm
git-rev-parse.html	64641	0644	edit dl rm
git-rev-parse.txt	15840	0644	edit dl rm
git-revert.html	26792	0644	edit dl rm
git-revert.txt	5421	0644	edit dl rm
git-rm.html	27584	0644	edit dl rm
git-rm.txt	7236	0644	edit dl rm
git-send-pack.html	24576	0644	edit dl rm
git-send-pack.txt	5160	0644	edit dl rm
git-sh-i18n--envsubst.html	18166	0644	edit dl rm
git-sh-i18n--envsubst.txt	928	0644	edit dl rm
git-sh-i18n.html	18595	0644	edit dl rm
git-sh-i18n.txt	1147	0644	edit dl rm
git-sh-setup.html	21277	0644	edit dl rm
git-sh-setup.txt	2976	0644	edit dl rm
git-shell.html	21414	0644	edit dl rm
git-shell.txt	2981	0644	edit dl rm
git-shortlog.html	64618	0644	edit dl rm
git-shortlog.txt	4409	0644	edit dl rm
git-show-branch.html	26813	0644	edit dl rm
git-show-branch.txt	6589	0644	edit dl rm
git-show-index.html	19521	0644	edit dl rm
git-show-index.txt	1473	0644	edit dl rm
git-show-ref.html	26075	0644	edit dl rm
git-show-ref.txt	6648	0644	edit dl rm
git-show.html	111644	0644	edit dl rm
git-show.txt	1929	0644	edit dl rm
git-sparse-checkout.html	43949	0644	edit dl rm
git-sparse-checkout.txt	21258	0644	edit dl rm
git-stage.html	17341	0644	edit dl rm
git-stage.txt	299	0644	edit dl rm
git-stash.html	38594	0644	edit dl rm
git-stash.txt	14999	0644	edit dl rm
git-status.html	45718	0644	edit dl rm
git-status.txt	20295	0644	edit dl rm
git-stripspace.html	20016	0644	edit dl rm
git-stripspace.txt	1946	0644	edit dl rm
git-submodule.html	45581	0644	edit dl rm
git-submodule.txt	20819	0644	edit dl rm
git-subtree.html	36823	0644	edit dl rm
git-subtree.txt	13687	0644	edit dl rm
git-switch.html	33314	0644	edit dl rm
git-switch.txt	8607	0644	edit dl rm
git-symbolic-ref.html	20452	0644	edit dl rm
git-symbolic-ref.txt	2327	0644	edit dl rm
git-tag.html	38958	0644	edit dl rm
git-tag.txt	13469	0644	edit dl rm
git-tools.html	17207	0644	edit dl rm
git-tools.txt	422	0644	edit dl rm
git-unpack-file.html	17645	0644	edit dl rm
git-unpack-file.txt	434	0644	edit dl rm
git-unpack-objects.html	18811	0644	edit dl rm
git-unpack-objects.txt	1220	0644	edit dl rm
git-update-index.html	49723	0644	edit dl rm
git-update-index.txt	23928	0644	edit dl rm
git-update-ref.html	25909	0644	edit dl rm
git-update-ref.txt	6298	0644	edit dl rm
git-update-server-info.html	18255	0644	edit dl rm
git-update-server-info.txt	801	0644	edit dl rm
git-upload-archive.html	19776	0644	edit dl rm
git-upload-archive.txt	2087	0644	edit dl rm
git-upload-pack.html	21671	0644	edit dl rm
git-upload-pack.txt	2998	0644	edit dl rm
git-var.html	21537	0644	edit dl rm
git-var.txt	3176	0644	edit dl rm
git-verify-commit.html	17948	0644	edit dl rm
git-verify-commit.txt	575	0644	edit dl rm
git-verify-pack.html	18953	0644	edit dl rm
git-verify-pack.txt	1111	0644	edit dl rm
git-verify-tag.html	17941	0644	edit dl rm
git-verify-tag.txt	562	0644	edit dl rm
git-version.html	17798	0644	edit dl rm
git-version.txt	532	0644	edit dl rm
git-web--browse.html	22405	0644	edit dl rm
git-web--browse.txt	3576	0644	edit dl rm
git-whatchanged.html	18572	0644	edit dl rm
git-whatchanged.txt	1098	0644	edit dl rm
git-worktree.html	46341	0644	edit dl rm
git-worktree.txt	20985	0644	edit dl rm
git-write-tree.html	18441	0644	edit dl rm
git-write-tree.txt	1026	0644	edit dl rm
git.html	107237	0644	edit dl rm
git.txt	43254	0644	edit dl rm
gitattributes.html	82845	0644	edit dl rm
gitattributes.txt	49511	0644	edit dl rm
gitcli.html	29584	0644	edit dl rm
gitcli.txt	9697	0644	edit dl rm
gitcore-tutorial.html	100139	0644	edit dl rm
gitcore-tutorial.txt	62240	0644	edit dl rm
gitcredentials.html	31980	0644	edit dl rm
gitcredentials.txt	11317	0644	edit dl rm
gitdiffcore.html	33745	0644	edit dl rm
gitdiffcore.txt	14082	0644	edit dl rm
giteveryday.html	38092	0644	edit dl rm
giteveryday.txt	14422	0644	edit dl rm
gitfaq.html	44081	0644	edit dl rm
gitfaq.txt	21069	0644	edit dl rm
gitformat-bundle.html	21446	0644	edit dl rm
gitformat-bundle.txt	3256	0644	edit dl rm
gitformat-chunk.html	24329	0644	edit dl rm
gitformat-chunk.txt	5560	0644	edit dl rm
gitformat-commit-graph.html	28630	0644	edit dl rm
gitformat-commit-graph.txt	7857	0644	edit dl rm
gitformat-index.html	40269	0644	edit dl rm
gitformat-index.txt	15180	0644	edit dl rm
gitformat-pack.html	49811	0644	edit dl rm
gitformat-pack.txt	23509	0644	edit dl rm
gitformat-signature.html	27362	0644	edit dl rm
gitformat-signature.txt	8093	0644	edit dl rm
gitglossary.html	64201	0644	edit dl rm
gitglossary.txt	358	0644	edit dl rm
githooks.html	56500	0644	edit dl rm
githooks.txt	29331	0644	edit dl rm
gitignore.html	28399	0644	edit dl rm
gitignore.txt	8918	0644	edit dl rm
gitmailmap.html	22819	0644	edit dl rm
gitmailmap.txt	3551	0644	edit dl rm
gitmodules.html	24057	0644	edit dl rm
gitmodules.txt	4800	0644	edit dl rm
gitnamespaces.html	22148	0644	edit dl rm
gitnamespaces.txt	2509	0644	edit dl rm
gitprotocol-capabilities.html	37425	0644	edit dl rm
gitprotocol-capabilities.txt	15311	0644	edit dl rm
gitprotocol-common.html	21565	0644	edit dl rm
gitprotocol-common.txt	3177	0644	edit dl rm
gitprotocol-http.html	43234	0644	edit dl rm
gitprotocol-http.txt	17994	0644	edit dl rm
gitprotocol-pack.html	53023	0644	edit dl rm
gitprotocol-pack.txt	27678	0644	edit dl rm
gitprotocol-v2.html	59690	0644	edit dl rm
gitprotocol-v2.txt	31434	0644	edit dl rm
gitremote-helpers.html	48215	0644	edit dl rm
gitremote-helpers.txt	21785	0644	edit dl rm
gitrepository-layout.html	39352	0644	edit dl rm
gitrepository-layout.txt	11622	0644	edit dl rm
gitrevisions.html	41621	0644	edit dl rm
gitrevisions.txt	823	0644	edit dl rm
gitsubmodules.html	31699	0644	edit dl rm
gitsubmodules.txt	10366	0644	edit dl rm
gittutorial-2.html	34547	0644	edit dl rm
gittutorial-2.txt	14750	0644	edit dl rm
gittutorial.html	46263	0644	edit dl rm
gittutorial.txt	22972	0644	edit dl rm
gitworkflows.html	39869	0644	edit dl rm
gitworkflows.txt	17414	0644	edit dl rm
glossary-content.txt	32609	0644	edit dl rm
howto-index.html	22991	0644	edit dl rm
howto-index.txt	4001	0644	edit dl rm
i18n.txt	2940	0644	edit dl rm
line-range-format.txt	1162	0644	edit dl rm
line-range-options.txt	761	0644	edit dl rm
merge-options.txt	7236	0644	edit dl rm
merge-strategies.txt	6610	0644	edit dl rm
mergetools-diff.txt	1507	0644	edit dl rm
mergetools-merge.txt	2586	0644	edit dl rm
MyFirstContribution.html	90572	0644	edit dl rm
MyFirstContribution.txt	54596	0644	edit dl rm
MyFirstObjectWalk.html	60554	0644	edit dl rm
MyFirstObjectWalk.txt	28979	0644	edit dl rm
object-format-disclaimer.txt	470	0644	edit dl rm
pretty-formats.txt	15669	0644	edit dl rm
pretty-options.txt	4201	0644	edit dl rm
pull-fetch-param.txt	5476	0644	edit dl rm
README.md	3652	0644	edit dl rm
ref-reachability-filters.txt	391	0644	edit dl rm
rerere-options.txt	414	0644	edit dl rm
rev-list-description.txt	2531	0644	edit dl rm
rev-list-options.txt	46906	0644	edit dl rm
ReviewingGuidelines.html	26831	0644	edit dl rm
ReviewingGuidelines.txt	8100	0644	edit dl rm
revisions.txt	17109	0644	edit dl rm
scalar.html	26055	0644	edit dl rm
scalar.txt	6056	0644	edit dl rm
sequencer.txt	472	0644	edit dl rm
signoff-option.txt	781	0644	edit dl rm
SubmittingPatches.html	55660	0644	edit dl rm
SubmittingPatches.txt	30147	0644	edit dl rm
ToolsForGit.html	19020	0644	edit dl rm
ToolsForGit.txt	1348	0644	edit dl rm
trace2-target-values.txt	529	0644	edit dl rm
transfer-data-leaks.txt	1712	0644	edit dl rm
urls-remotes.txt	2642	0644	edit dl rm
urls.txt	3634	0644	edit dl rm
user-manual.html	275731	0644	edit dl rm
user-manual.txt	173518	0644	edit dl rm

Edit: /usr/share/doc/git/MyFirstObjectWalk.txt (28979B)

= My First Object Walk

== What's an Object Walk?

The object walk is a key concept in Git - this is the process that underpins
operations like object transfer and fsck. Beginning from a given commit, the
list of objects is found by walking parent relationships between commits (commit
X based on commit W) and containment relationships between objects (tree Y is
contained within commit X, and blob Z is located within tree Y, giving our
working tree for commit X something like `y/z.txt`).

A related concept is the revision walk, which is focused on commit objects and
their parent relationships and does not delve into other object types. The
revision walk is used for operations like `git log`.

=== Related Reading

- `Documentation/user-manual.txt` under "Hacking Git" contains some coverage of
  the revision walker in its various incarnations.
- `revision.h`
- https://eagain.net/articles/git-for-computer-scientists/[Git for Computer Scientists]
  gives a good overview of the types of objects in Git and what your object
  walk is really describing.

== Setting Up

Create a new branch from `master`.

----
git checkout -b revwalk origin/master
----

We'll put our fiddling into a new command. For fun, let's name it `git walken`.
Open up a new file `builtin/walken.c` and set up the command handler:

----
/*
 * "git walken"
 *
 * Part of the "My First Object Walk" tutorial.
 */

#include "builtin.h"
#include "trace.h"

int cmd_walken(int argc, const char **argv, const char *prefix)
{
	trace_printf(_("cmd_walken incoming...\n"));
	return 0;
}
----

NOTE: `trace_printf()`, defined in `trace.h`, differs from `printf()` in
that it can be turned on or off at runtime. For the purposes of this
tutorial, we will write `walken` as though it is intended for use as
a "plumbing" command: that is, a command which is used primarily in
scripts, rather than interactively by humans (a "porcelain" command).
So we will send our debug output to `trace_printf()` instead.
When running, enable trace output by setting the environment variable `GIT_TRACE`.

Add usage text and `-h` handling, like all subcommands should consistently do
(our test suite will notice and complain if you fail to do so).
We'll need to include the `parse-options.h` header.

----
#include "parse-options.h"

...

int cmd_walken(int argc, const char **argv, const char *prefix)
{
	const char * const walken_usage[] = {
		N_("git walken"),
		NULL,
	};
	struct option options[] = {
		OPT_END()
	};

argc = parse_options(argc, argv, prefix, options, walken_usage, 0);

...
}
----

Also add the relevant line in `builtin.h` near `cmd_whatchanged()`:

----
int cmd_walken(int argc, const char **argv, const char *prefix);
----

Include the command in `git.c` in `commands[]` near the entry for `whatchanged`,
maintaining alphabetical ordering:

----
{ "walken", cmd_walken, RUN_SETUP },
----

Add it to the `Makefile` near the line for `builtin/worktree.o`:

----
BUILTIN_OBJS += builtin/walken.o
----

Build and test out your command, without forgetting to ensure the `DEVELOPER`
flag is set, and with `GIT_TRACE` enabled so the debug output can be seen:

----
$ echo DEVELOPER=1 >>config.mak
$ make
$ GIT_TRACE=1 ./bin-wrappers/git walken
----

NOTE: For a more exhaustive overview of the new command process, take a look at
`Documentation/MyFirstContribution.txt`.

NOTE: A reference implementation can be found at
https://github.com/nasamuffin/git/tree/revwalk.

=== `struct rev_cmdline_info`

The definition of `struct rev_cmdline_info` can be found in `revision.h`.

This struct is contained within the `rev_info` struct and is used to reflect
parameters provided by the user over the CLI.

`nr` represents the number of `rev_cmdline_entry` present in the array.

`alloc` is used by the `ALLOC_GROW` macro. Check `alloc.h` - this variable is
used to track the allocated size of the list.

Per entry, we find:

`item` is the object provided upon which to base the object walk. Items in Git
can be blobs, trees, commits, or tags. (See `Documentation/gittutorial-2.txt`.)

`name` is the object ID (OID) of the object - a hex string you may be familiar
with from using Git to organize your source in the past. Check the tutorial
mentioned above towards the top for a discussion of where the OID can come
from.

`whence` indicates some information about what to do with the parents of the
specified object. We'll explore this flag more later on; take a look at
`Documentation/revisions.txt` to get an idea of what could set the `whence`
value.

`flags` are used to hint the beginning of the revision walk and are the first
block under the `#include`s in `revision.h`. The most likely ones to be set in
the `rev_cmdline_info` are `UNINTERESTING` and `BOTTOM`, but these same flags
can be used during the walk, as well.

=== `struct rev_info`

This one is quite a bit longer, and many fields are only used during the walk
by `revision.c` - not configuration options. Most of the configurable flags in
`struct rev_info` have a mirror in `Documentation/rev-list-options.txt`. It's a
good idea to take some time and read through that document.

== Basic Commit Walk

First, let's see if we can replicate the output of `git log --oneline`. We'll
refer back to the implementation frequently to discover norms when performing
an object walk of our own.

To do so, we'll first find all the commits, in order, which preceded the current
commit. We'll extract the name and subject of the commit from each.

Ideally, we will also be able to find out which ones are currently at the tip of
various branches.

=== Setting Up

Preparing for your object walk has some distinct stages.

1. Perform default setup for this mode, and others which may be invoked.
2. Check configuration files for relevant settings.
3. Set up the `rev_info` struct.
4. Tweak the initialized `rev_info` to suit the current walk.
5. Prepare the `rev_info` for the walk.
6. Iterate over the objects, processing each one.

==== Default Setups

Before examining configuration files which may modify command behavior, set up
default state for switches or options your command may have. If your command
utilizes other Git components, ask them to set up their default states as well.
For instance, `git log` takes advantage of `grep` and `diff` functionality, so
its `init_log_defaults()` sets its own state (`decoration_style`) and asks
`grep` and `diff` to initialize themselves by calling each of their
initialization functions.

==== Configuring From `.gitconfig`

Next, we should have a look at any relevant configuration settings (i.e.,
settings readable and settable from `git config`). This is done by providing a
callback to `git_config()`; within that callback, you can also invoke methods
from other components you may need that need to intercept these options. Your
callback will be invoked once per each configuration value which Git knows about
(global, local, worktree, etc.).

Similarly to the default values, we don't have anything to do here yet
ourselves; however, we should call `git_default_config()` if we aren't calling
any other existing config callbacks.

Add a new function to `builtin/walken.c`.
We'll also need to include the `config.h` header:

----
#include "config.h"

...

static int git_walken_config(const char *var, const char *value, void *cb)
{
	/*
	 * For now, we don't have any custom configuration, so fall back to
	 * the default config.
	 */
	return git_default_config(var, value, cb);
}
----

Make sure to invoke `git_config()` with it in your `cmd_walken()`:

----
int cmd_walken(int argc, const char **argv, const char *prefix)
{
	...

git_config(git_walken_config, NULL);

...
}
----

==== Setting Up `rev_info`

Now that we've gathered external configuration and options, it's time to
initialize the `rev_info` object which we will use to perform the walk. This is
typically done by calling `repo_init_revisions()` with the repository you intend
to target, as well as the `prefix` argument of `cmd_walken` and your `rev_info`
struct.

Add the `struct rev_info` and the `repo_init_revisions()` call.
We'll also need to include the `revision.h` header:

----
#include "revision.h"

...

int cmd_walken(int argc, const char **argv, const char *prefix)
{
	/* This can go wherever you like in your declarations.*/
	struct rev_info rev;
	...

/* This should go after the git_config() call. */
	repo_init_revisions(the_repository, &rev, prefix);

...
}
----

==== Tweaking `rev_info` For the Walk

We're getting close, but we're still not quite ready to go. Now that `rev` is
initialized, we can modify it to fit our needs. This is usually done within a
helper for clarity, so let's add one:

----
static void final_rev_info_setup(struct rev_info *rev)
{
	/*
	 * We want to mimic the appearance of `git log --oneline`, so let's
	 * force oneline format.
	 */
	get_commit_format("oneline", rev);

/* Start our object walk at HEAD. */
	add_head_to_pending(rev);
}
----

[NOTE]
====
Instead of using the shorthand `add_head_to_pending()`, you could do
something like this:
----
	struct setup_revision_opt opt;

memset(&opt, 0, sizeof(opt));
	opt.def = "HEAD";
	opt.revarg_opt = REVARG_COMMITTISH;
	setup_revisions(argc, argv, rev, &opt);
----
Using a `setup_revision_opt` gives you finer control over your walk's starting
point.
====

Then let's invoke `final_rev_info_setup()` after the call to
`repo_init_revisions()`:

----
int cmd_walken(int argc, const char **argv, const char *prefix)
{
	...

final_rev_info_setup(&rev);

...
}
----

Later, we may wish to add more arguments to `final_rev_info_setup()`. But for
now, this is all we need.

==== Preparing `rev_info` For the Walk

Now that `rev` is all initialized and configured, we've got one more setup step
before we get rolling. We can do this in a helper, which will both prepare the
`rev_info` for the walk, and perform the walk itself. Let's start the helper
with the call to `prepare_revision_walk()`, which can return an error without
dying on its own:

----
static void walken_commit_walk(struct rev_info *rev)
{
	if (prepare_revision_walk(rev))
		die(_("revision walk setup failed"));
}
----

NOTE: `die()` prints to `stderr` and exits the program. Since it will print to
`stderr` it's likely to be seen by a human, so we will localize it.

==== Performing the Walk!

Finally! We are ready to begin the walk itself. Now we can see that `rev_info`
can also be used as an iterator; we move to the next item in the walk by using
`get_revision()` repeatedly. Add the listed variable declarations at the top and
the walk loop below the `prepare_revision_walk()` call within your
`walken_commit_walk()`:

----
#include "pretty.h"

...

static void walken_commit_walk(struct rev_info *rev)
{
	struct commit *commit;
	struct strbuf prettybuf = STRBUF_INIT;

...

while ((commit = get_revision(rev))) {
		strbuf_reset(&prettybuf);
		pp_commit_easy(CMIT_FMT_ONELINE, commit, &prettybuf);
		puts(prettybuf.buf);
	}
	strbuf_release(&prettybuf);
}
----

NOTE: `puts()` prints a `char*` to `stdout`. Since this is the part of the
command we expect to be machine-parsed, we're sending it directly to stdout.

Give it a shot.

----
$ make
$ ./bin-wrappers/git walken
----

You should see all of the subject lines of all the commits in
your tree's history, in order, ending with the initial commit, "Initial revision
of "git", the information manager from hell". Congratulations! You've written
your first revision walk. You can play with printing some additional fields
from each commit if you're curious; have a look at the functions available in
`commit.h`.

=== Adding a Filter

Next, let's try to filter the commits we see based on their author. This is
equivalent to running `git log --author=<pattern>`. We can add a filter by
modifying `rev_info.grep_filter`, which is a `struct grep_opt`.

First some setup. Add `grep_config()` to `git_walken_config()`:

----
static int git_walken_config(const char *var, const char *value, void *cb)
{
	grep_config(var, value, cb);
	return git_default_config(var, value, cb);
}
----

Next, we can modify the `grep_filter`. This is done with convenience functions
found in `grep.h`. For fun, we're filtering to only commits from folks using a
`gmail.com` email address - a not-very-precise guess at who may be working on
Git as a hobby. Since we're checking the author, which is a specific line in the
header, we'll use the `append_header_grep_pattern()` helper. We can use
the `enum grep_header_field` to indicate which part of the commit header we want
to search.

In `final_rev_info_setup()`, add your filter line:

----
static void final_rev_info_setup(int argc, const char **argv,
		const char *prefix, struct rev_info *rev)
{
	...

append_header_grep_pattern(&rev->grep_filter, GREP_HEADER_AUTHOR,
		"gmail");
	compile_grep_patterns(&rev->grep_filter);

...
}
----

`append_header_grep_pattern()` adds your new "gmail" pattern to `rev_info`, but
it won't work unless we compile it with `compile_grep_patterns()`.

NOTE: If you are using `setup_revisions()` (for example, if you are passing a
`setup_revision_opt` instead of using `add_head_to_pending()`), you don't need
to call `compile_grep_patterns()` because `setup_revisions()` calls it for you.

NOTE: We could add the same filter via the `append_grep_pattern()` helper if we
wanted to, but `append_header_grep_pattern()` adds the `enum grep_context` and
`enum grep_pat_token` for us.

=== Changing the Order

There are a few ways that we can change the order of the commits during a
revision walk. Firstly, we can use the `enum rev_sort_order` to choose from some
typical orderings.

`topo_order` is the same as `git log --topo-order`: we avoid showing a parent
before all of its children have been shown, and we avoid mixing commits which
are in different lines of history. (`git help log`'s section on `--topo-order`
has a very nice diagram to illustrate this.)

Let's see what happens when we run with `REV_SORT_BY_COMMIT_DATE` as opposed to
`REV_SORT_BY_AUTHOR_DATE`. Add the following:

----
static void final_rev_info_setup(int argc, const char **argv,
		const char *prefix, struct rev_info *rev)
{
	...

rev->topo_order = 1;
	rev->sort_order = REV_SORT_BY_COMMIT_DATE;

...
}
----

Let's output this into a file so we can easily diff it with the walk sorted by
author date.

----
$ make
$ ./bin-wrappers/git walken > commit-date.txt
----

Then, let's sort by author date and run it again.

----
static void final_rev_info_setup(int argc, const char **argv,
		const char *prefix, struct rev_info *rev)
{
	...

rev->topo_order = 1;
	rev->sort_order = REV_SORT_BY_AUTHOR_DATE;

...
}
----

----
$ make
$ ./bin-wrappers/git walken > author-date.txt
----

Finally, compare the two. This is a little less helpful without object names or
dates, but hopefully we get the idea.

----
$ diff -u commit-date.txt author-date.txt
----

This display indicates that commits can be reordered after they're written, for
example with `git rebase`.

Let's try one more reordering of commits. `rev_info` exposes a `reverse` flag.
Set that flag somewhere inside of `final_rev_info_setup()`:

----
static void final_rev_info_setup(int argc, const char **argv, const char *prefix,
		struct rev_info *rev)
{
	...

rev->reverse = 1;

...
}
----

Run your walk again and note the difference in order. (If you remove the grep
pattern, you should see the last commit this call gives you as your current
HEAD.)

== Basic Object Walk

So far we've been walking only commits. But Git has more types of objects than
that! Let's see if we can walk _all_ objects, and find out some information
about each one.

We can base our work on an example. `git pack-objects` prepares all kinds of
objects for packing into a bitmap or packfile. The work we are interested in
resides in `builtins/pack-objects.c:get_object_list()`; examination of that
function shows that the all-object walk is being performed by
`traverse_commit_list()` or `traverse_commit_list_filtered()`. Those two
functions reside in `list-objects.c`; examining the source shows that, despite
the name, these functions traverse all kinds of objects. Let's have a look at
the arguments to `traverse_commit_list()`.

- `struct rev_info *revs`: This is the `rev_info` used for the walk. If
  its `filter` member is not `NULL`, then `filter` contains information for
  how to filter the object list.
- `show_commit_fn show_commit`: A callback which will be used to handle each
  individual commit object.
- `show_object_fn show_object`: A callback which will be used to handle each
  non-commit object (so each blob, tree, or tag).
- `void *show_data`: A context buffer which is passed in turn to `show_commit`
  and `show_object`.

In addition, `traverse_commit_list_filtered()` has an additional parameter:

- `struct oidset *omitted`: A linked-list of object IDs which the provided
  filter caused to be omitted.

It looks like these methods use callbacks we provide instead of needing us
to call it repeatedly ourselves. Cool! Let's add the callbacks first.

For the sake of this tutorial, we'll simply keep track of how many of each kind
of object we find. At file scope in `builtin/walken.c` add the following
tracking variables:

----
static int commit_count;
static int tag_count;
static int blob_count;
static int tree_count;
----

Commits are handled by a different callback than other objects; let's do that
one first:

----
static void walken_show_commit(struct commit *cmt, void *buf)
{
	commit_count++;
}
----

The `cmt` argument is fairly self-explanatory. But it's worth mentioning that
the `buf` argument is actually the context buffer that we can provide to the
traversal calls - `show_data`, which we mentioned a moment ago.

Since we have the `struct commit` object, we can look at all the same parts that
we looked at in our earlier commit-only walk. For the sake of this tutorial,
though, we'll just increment the commit counter and move on.

The callback for non-commits is a little different, as we'll need to check
which kind of object we're dealing with:

----
static void walken_show_object(struct object *obj, const char *str, void *buf)
{
	switch (obj->type) {
	case OBJ_TREE:
		tree_count++;
		break;
	case OBJ_BLOB:
		blob_count++;
		break;
	case OBJ_TAG:
		tag_count++;
		break;
	case OBJ_COMMIT:
		BUG("unexpected commit object in walken_show_object\n");
	default:
		BUG("unexpected object type %s in walken_show_object\n",
			type_name(obj->type));
	}
}
----

Again, `obj` is fairly self-explanatory, and we can guess that `buf` is the same
context pointer that `walken_show_commit()` receives: the `show_data` argument
to `traverse_commit_list()` and `traverse_commit_list_filtered()`. Finally,
`str` contains the name of the object, which ends up being something like
`foo.txt` (blob), `bar/baz` (tree), or `v1.2.3` (tag).

To help assure us that we aren't double-counting commits, we'll include some
complaining if a commit object is routed through our non-commit callback; we'll
also complain if we see an invalid object type. Since those two cases should be
unreachable, and would only change in the event of a semantic change to the Git
codebase, we complain by using `BUG()` - which is a signal to a developer that
the change they made caused unintended consequences, and the rest of the
codebase needs to be updated to understand that change. `BUG()` is not intended
to be seen by the public, so it is not localized.

Our main object walk implementation is substantially different from our commit
walk implementation, so let's make a new function to perform the object walk. We
can perform setup which is applicable to all objects here, too, to keep separate
from setup which is applicable to commit-only walks.

We'll start by enabling all types of objects in the `struct rev_info`.  We'll
also turn on `tree_blobs_in_commit_order`, which means that we will walk a
commit's tree and everything it points to immediately after we find each commit,
as opposed to waiting for the end and walking through all trees after the commit
history has been discovered. With the appropriate settings configured, we are
ready to call `prepare_revision_walk()`.

----
static void walken_object_walk(struct rev_info *rev)
{
	rev->tree_objects = 1;
	rev->blob_objects = 1;
	rev->tag_objects = 1;
	rev->tree_blobs_in_commit_order = 1;

if (prepare_revision_walk(rev))
		die(_("revision walk setup failed"));

commit_count = 0;
	tag_count = 0;
	blob_count = 0;
	tree_count = 0;
----

Let's start by calling just the unfiltered walk and reporting our counts.
Complete your implementation of `walken_object_walk()`.
We'll also need to include the `list-objects.h` header.

----
#include "list-objects.h"

...

traverse_commit_list(rev, walken_show_commit, walken_show_object, NULL);

printf("commits %d\nblobs %d\ntags %d\ntrees %d\n", commit_count,
		blob_count, tag_count, tree_count);
}
----

NOTE: This output is intended to be machine-parsed. Therefore, we are not
sending it to `trace_printf()`, and we are not localizing it - we need scripts
to be able to count on the formatting to be exactly the way it is shown here.
If we were intending this output to be read by humans, we would need to localize
it with `_()`.

Finally, we'll ask `cmd_walken()` to use the object walk instead. Discussing
command line options is out of scope for this tutorial, so we'll just hardcode
a branch we can change at compile time. Where you call `final_rev_info_setup()`
and `walken_commit_walk()`, instead branch like so:

----
	if (1) {
		add_head_to_pending(&rev);
		walken_object_walk(&rev);
	} else {
		final_rev_info_setup(argc, argv, prefix, &rev);
		walken_commit_walk(&rev);
	}
----

NOTE: For simplicity, we've avoided all the filters and sorts we applied in
`final_rev_info_setup()` and simply added `HEAD` to our pending queue. If you
want, you can certainly use the filters we added before by moving
`final_rev_info_setup()` out of the conditional and removing the call to
`add_head_to_pending()`.

Now we can try to run our command! It should take noticeably longer than the
commit walk, but an examination of the output will give you an idea why. Your
output should look similar to this example, but with different counts:

----
Object walk completed. Found 55733 commits, 100274 blobs, 0 tags, and 104210 trees.
----

This makes sense. We have more trees than commits because the Git project has
lots of subdirectories which can change, plus at least one tree per commit. We
have no tags because we started on a commit (`HEAD`) and while tags can point to
commits, commits can't point to tags.

NOTE: You will have different counts when you run this yourself! The number of
objects grows along with the Git project.

=== Adding a Filter

There are a handful of filters that we can apply to the object walk laid out in
`Documentation/rev-list-options.txt`. These filters are typically useful for
operations such as creating packfiles or performing a partial clone. They are
defined in `list-objects-filter-options.h`. For the purposes of this tutorial we
will use the "tree:1" filter, which causes the walk to omit all trees and blobs
which are not directly referenced by commits reachable from the commit in
`pending` when the walk begins. (`pending` is the list of objects which need to
be traversed during a walk; you can imagine a breadth-first tree traversal to
help understand. In our case, that means we omit trees and blobs not directly
referenced by `HEAD` or `HEAD`'s history, because we begin the walk with only
`HEAD` in the `pending` list.)

For now, we are not going to track the omitted objects, so we'll replace those
parameters with `NULL`. For the sake of simplicity, we'll add a simple
build-time branch to use our filter or not. Preface the line calling
`traverse_commit_list()` with the following, which will remind us which kind of
walk we've just performed:

----
	if (0) {
		/* Unfiltered: */
		trace_printf(_("Unfiltered object walk.\n"));
	} else {
		trace_printf(
			_("Filtered object walk with filterspec 'tree:1'.\n"));
		CALLOC_ARRAY(rev->filter, 1);
		parse_list_objects_filter(rev->filter, "tree:1");
	}
	traverse_commit_list(rev, walken_show_commit,
			     walken_show_object, NULL);
----

The `rev->filter` member is usually built directly from a command
line argument, so the module provides an easy way to build one from a string.
Even though we aren't taking user input right now, we can still build one with
a hardcoded string using `parse_list_objects_filter()`.

With the filter spec "tree:1", we are expecting to see _only_ the root tree for
each commit; therefore, the tree object count should be less than or equal to
the number of commits. (For an example of why that's true: `git commit --revert`
points to the same tree object as its grandparent.)

=== Counting Omitted Objects

We also have the capability to enumerate all objects which were omitted by a
filter, like with `git log --filter=<spec> --filter-print-omitted`. Asking
`traverse_commit_list_filtered()` to populate the `omitted` list means that our
object walk does not perform any better than an unfiltered object walk; all
reachable objects are walked in order to populate the list.

First, add the `struct oidset` and related items we will use to iterate it:

----
#include "oidset.h"

...

static void walken_object_walk(
	...

struct oidset omitted;
	struct oidset_iter oit;
	struct object_id *oid = NULL;
	int omitted_count = 0;
	oidset_init(&omitted, 0);

...
----

Modify the call to `traverse_commit_list_filtered()` to include your `omitted`
object:

----
	...

traverse_commit_list_filtered(rev,
			walken_show_commit, walken_show_object, NULL, &omitted);

...
----

Then, after your traversal, the `oidset` traversal is pretty straightforward.
Count all the objects within and modify the print statement:

----
	/* Count the omitted objects. */
	oidset_iter_init(&omitted, &oit);

while ((oid = oidset_iter_next(&oit)))
		omitted_count++;

printf("commits %d\nblobs %d\ntags %d\ntrees %d\nomitted %d\n",
		commit_count, blob_count, tag_count, tree_count, omitted_count);
----

By running your walk with and without the filter, you should find that the total
object count in each case is identical. You can also time each invocation of
the `walken` subcommand, with and without `omitted` being passed in, to confirm
to yourself the runtime impact of tracking all omitted objects.

=== Changing the Order

Finally, let's demonstrate that you can also reorder walks of all objects, not
just walks of commits. First, we'll make our handlers chattier - modify
`walken_show_commit()` and `walken_show_object()` to print the object as they
go:

----
#include "hex.h"

...

static void walken_show_commit(struct commit *cmt, void *buf)
{
	trace_printf("commit: %s\n", oid_to_hex(&cmt->object.oid));
	commit_count++;
}

static void walken_show_object(struct object *obj, const char *str, void *buf)
{
	trace_printf("%s: %s\n", type_name(obj->type), oid_to_hex(&obj->oid));

...
}
----

NOTE: Since we will be examining this output directly as humans, we'll use
`trace_printf()` here. Additionally, since this change introduces a significant
number of printed lines, using `trace_printf()` will allow us to easily silence
those lines without having to recompile.

(Leave the counter increment logic in place.)

With only that change, run again (but save yourself some scrollback):

----
$ GIT_TRACE=1 ./bin-wrappers/git walken | head -n 10
----

Take a look at the top commit with `git show` and the object ID you printed; it
should be the same as the output of `git show HEAD`.

Next, let's change a setting on our `struct rev_info` within
`walken_object_walk()`. Find where you're changing the other settings on `rev`,
such as `rev->tree_objects` and `rev->tree_blobs_in_commit_order`, and add the
`reverse` setting at the bottom:

----
	...

rev->tree_objects = 1;
	rev->blob_objects = 1;
	rev->tag_objects = 1;
	rev->tree_blobs_in_commit_order = 1;
	rev->reverse = 1;

...
----

Now, run again, but this time, let's grab the last handful of objects instead
of the first handful:

----
$ make
$ GIT_TRACE=1 ./bin-wrappers git walken | tail -n 10
----

The last commit object given should have the same OID as the one we saw at the
top before, and running `git show <oid>` with that OID should give you again
the same results as `git show HEAD`. Furthermore, if you run and examine the
first ten lines again (with `head` instead of `tail` like we did before applying
the `reverse` setting), you should see that now the first commit printed is the
initial commit, `e83c5163`.

== Wrapping Up

Let's review. In this tutorial, we:

- Built a commit walk from the ground up
- Enabled a grep filter for that commit walk
- Changed the sort order of that filtered commit walk
- Built an object walk (tags, commits, trees, and blobs) from the ground up
- Learned how to add a filter-spec to an object walk
- Changed the display order of the filtered object walk

cmd: