config/alias.txt: document alias accepting non-command first word

One can see that an alias that begins with a non-command first word, such as `loud-rebase = -c commit.verbose=true rebase`, is permitted. However, this isn't immediately obvious to users as alias instances typically begin with a command. Document the fact that an alias can begin with a non-command first word so that users will be able to discover that this is a feature. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Denton Liu committed Jun 5, 2019 at 16:10 UTC 459842e1c2777812130545dc52753c6f4d517e21
1 file changed +10
Documentation/config/alias.txt
+10
@@ -7,6 +7,16 @@ alias.*::
7 spaces, the usual shell quoting and escaping is supported.
8 A quote pair or a backslash can be used to quote them.
9 +
10 +Note that the first word of an alias does not necessarily have to be a
11 +command. It can be a command-line option that will be passed into the
12 +invocation of `git`. In particular, this is useful when used with `-c`
13 +to pass in one-time configurations or `-p` to force pagination. For example,
14 +`loud-rebase = -c commit.verbose=true rebase` can be defined such that
15 +running `git loud-rebase` would be equivalent to
16 +`git -c commit.verbose=true rebase`. Also, `ps = -p status` would be a
17 +helpful alias since `git ps` would paginate the output of `git status`
18 +where the original command does not.
19 ++
20 If the alias expansion is prefixed with an exclamation point,
21 it will be treated as a shell command. For example, defining
22 `alias.new = !gitk --all --not ORIG_HEAD`, the invocation