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From: Ian Wienand <iwienand@redhat•com>
To: git@vger•kernel.org
Cc: Ian Wienand <iwienand@redhat•com>
Subject: [PATCH v7 2/3] Documentation: alias: add notes on shell expansion
Date: Mon, 27 May 2024 10:30:48 +1000	[thread overview]
Message-ID: <20240527003208.1565249-2-iwienand@redhat.com> (raw)
In-Reply-To: <20240527003208.1565249-1-iwienand@redhat.com>

When writing inline shell for shell-expansion aliases (i.e. prefixed
with "!"), there are some caveats around argument parsing to be aware
of.  This series of notes attempts to explain what is happening more
clearly.

Signed-off-by: Ian Wienand <iwienand@redhat•com>
---
 Documentation/config/alias.txt | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/config/alias.txt b/Documentation/config/alias.txt
index 40851ef429..75f9f5e26f 100644
--- a/Documentation/config/alias.txt
+++ b/Documentation/config/alias.txt
@@ -27,3 +27,17 @@ it will be treated as a shell command.  For example, defining
   repository, which may not necessarily be the current directory.
 * `GIT_PREFIX` is set as returned by running `git rev-parse --show-prefix`
   from the original current directory. See linkgit:git-rev-parse[1].
+* Shell command aliases always receive any extra arguments provided to
+  the Git command-line as positional arguments.
+** Care should be taken if your shell alias is a "one-liner" script
+   with multiple commands (e.g. in a pipeline), references multiple
+   arguments, or is otherwise not able to handle positional arguments
+   appended via `"$@"`.  For example: `alias.cmd = "!echo $1 | grep
+   $2"` called as `git cmd 1 2` will be executed as 'echo $1 | grep $2
+   1 2', which is not what you want.
+** A convenient way to deal with this is to write your script
+   operations in an inline function that is then called with any
+   arguments from the command-line.  For example `alias.cmd = "!c() {
+   echo $1 | grep $2 ; }; c" will correctly execute the prior example.
+** Setting `GIT_TRACE=1` can help you debug the command being run for
+   your alias.
-- 
2.45.1


  reply	other threads:[~2024-05-27  0:32 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-22  2:41 [PATCH] alias: document caveats and add trace of prepared command Ian Wienand
2024-05-22  3:29 ` Eric Sunshine
2024-05-22 16:07 ` Junio C Hamano
2024-05-23  0:38   ` Ian Wienand
2024-05-23  4:20 ` [PATCH v2 1/3] Documentation: alias: rework notes into points Ian Wienand
2024-05-23  4:20   ` [PATCH v2 2/3] Documentation: alias: add notes on shell expansion Ian Wienand
2024-05-23  4:20   ` [PATCH v2 3/3] run-command: show prepared command Ian Wienand
2024-05-23  4:27   ` [PATCH v2 1/3] Documentation: alias: rework notes into points Eric Sunshine
2024-05-23  4:39     ` Ian Wienand
2024-05-23  4:37   ` [PATCH v3 " Ian Wienand
2024-05-23  4:37     ` [PATCH v3 2/3] Documentation: alias: add notes on shell expansion Ian Wienand
2024-05-23  4:37     ` [PATCH v3 3/3] run-command: show prepared command Ian Wienand
2024-05-23 15:29       ` Junio C Hamano
2024-05-23 23:40         ` Junio C Hamano
2024-05-24  6:09           ` Junio C Hamano
2024-05-24  7:18             ` Ian Wienand
2024-05-24 15:33               ` Junio C Hamano
2024-05-24  0:43         ` Ian Wienand
2024-05-24 17:50           ` Junio C Hamano
2024-05-25  1:13             ` Ian Wienand
2024-05-23 15:14     ` [PATCH v3 1/3] Documentation: alias: rework notes into points Junio C Hamano
2024-05-24  7:32     ` [PATCH v4 " Ian Wienand
2024-05-24  7:32       ` [PATCH v4 2/3] Documentation: alias: add notes on shell expansion Ian Wienand
2024-05-24  7:32       ` [PATCH v4 3/3] run-command: show prepared command Ian Wienand
2024-05-24 19:16         ` Junio C Hamano
2024-05-24 19:58           ` Junio C Hamano
2024-05-25  1:14           ` Ian Wienand
2024-05-25  1:20       ` [PATCH v5 1/3] Documentation: alias: rework notes into points Ian Wienand
2024-05-25  1:20         ` [PATCH v5 2/3] Documentation: alias: add notes on shell expansion Ian Wienand
2024-05-25  1:20         ` [PATCH v5 3/3] run-command: show prepared command Ian Wienand
2024-05-25  5:44           ` Junio C Hamano
2024-05-25  6:06           ` Junio C Hamano
2024-05-25 23:49             ` Ian Wienand
2024-05-25 23:44         ` [PATCH v6 1/3] Documentation: alias: rework notes into points Ian Wienand
2024-05-25 23:44           ` [PATCH v6 2/3] Documentation: alias: add notes on shell expansion Ian Wienand
2024-05-26 23:26             ` Junio C Hamano
2024-05-27  0:22               ` Ian Wienand
2024-05-25 23:44           ` [PATCH v6 3/3] run-command: show prepared command Ian Wienand
2024-05-26 16:20             ` Junio C Hamano
2024-05-27  0:30           ` [PATCH v7 1/3] Documentation: alias: rework notes into points Ian Wienand
2024-05-27  0:30             ` Ian Wienand [this message]
2024-05-27 17:48               ` [PATCH v7 2/3] Documentation: alias: add notes on shell expansion Junio C Hamano
2024-05-27  0:30             ` [PATCH v7 3/3] run-command: show prepared command Ian Wienand

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