Junio C Hamano <gitster@xxxxxxxxx> writes:
> Theodore Tso <tytso@xxxxxxx> writes:
>
>> On Wed, Jun 25, 2008 at 01:50:06PM -0700, Junio C Hamano wrote:
>>> I just replied to Avery about that. -- is always the way to disambiguate
>>> between refs (that come before --) and paths (that come after --), not
>>> limited to "git checkout" but with other commands such as "git log", "git
>>> diff", etc.
>>
>> Stupid quesiton --- where is this documented? I don't see this
>> documented either in the man page for git or git-checkout.
>
> You are asking a wrong person. My git knowledge mostly comes from
> yearlong reading of the mailing list articles, and doing a bit myself also
> helps ;-).
I couldn't find a good central place to place this as this is more or less
used consistently throughout the UI (log, diff, grep, and then I just
fixed reset as well).
Whereever the description should end up to be in, here is what I think we
should talk about.
Documentation/gitcli.txt | 37 +++++++++++++++++++++++++++++++++----
1 files changed, 33 insertions(+), 4 deletions(-)
diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt
index 8fb5d88..2316049 100644
--- a/Documentation/gitcli.txt
+++ b/Documentation/gitcli.txt
@@ -13,8 +13,37 @@ gitcli
DESCRIPTION
-----------
-This manual describes best practice in how to use git CLI. Here are
-the rules that you should follow when you are scripting git:
+This manual describes the convention used throughout git CLI.
+
+Many commands take revisions (most often "commits", but sometimes
+"tree-ish", depending on the context and command) and paths as their
+arguments. Here are the rules:
+
+ * Revisions come first and then paths.
+ E.g. in `git diff v1.0 v2.0 arch/x86 include/asm-x86`,
+ `v1.0` and `v2.0` are revisions and `arch/x86` and `include/asm-x86`
+ are paths.
+
+ * When an argument can be misunderstood as either a revision or a path,
+ they can be disambiguated by placing `\--` between them.
+ E.g. `git diff \-- HEAD` is, "I have a file called HEAD in my work
+ tree. Please show changes between the version I staged in the index
+ and what I have in the work tree for that file". not "show difference
+ between the HEAD commit and the work tree as a whole". You can say
+ `git diff HEAD \--` to ask for the latter.
+
+ * Without disambiguating `\--`, git makes a reasonable guess, but errors
+ out and asking you to disambiguate when ambiguous. E.g. if you have a
+ file called HEAD in your work tree, `git diff HEAD` is ambiguous, and
+ you have to say either `git diff HEAD \--` or `git diff \-- HEAD` to
+ disambiguate.
+
+When writing a script that is expected to handle random user-input, it is
+a good practice to make it explicit which arguments are which by placing
+disambiguating `\--` at appropriate places.
+
+Here are the rules regarding the "flags" that you should follow when you are
+scripting git:
* it's preferred to use the non dashed form of git commands, which means that
you should prefer `"git foo"` to `"git-foo"`.
@@ -34,8 +63,8 @@ the rules that you should follow when you are scripting git:
if you happen to have a file called `HEAD` in the work tree.
-ENHANCED CLI
-------------
+ENHANCED OPTION PARSER
+----------------------
From the git 1.5.4 series and further, many git commands (not all of them at the
time of the writing though) come with an enhanced option parser.
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