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[203.12.11.234]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6a35969bcd5sm80952706d6.53.2024.05.22.21.38.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 May 2024 21:38:25 -0700 (PDT) From: Ian Wienand To: git@vger.kernel.org Cc: Ian Wienand Subject: [PATCH v3 2/3] Documentation: alias: add notes on shell expansion Date: Thu, 23 May 2024 14:37:55 +1000 Message-ID: <20240523043806.1223032-2-iwienand@redhat.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240523043806.1223032-1-iwienand@redhat.com> References: <20240523042143.1220862-1-iwienand@redhat.com> <20240523043806.1223032-1-iwienand@redhat.com> Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 --- Documentation/config/alias.txt | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/Documentation/config/alias.txt b/Documentation/config/alias.txt index 40851ef429..51fa876c91 100644 --- a/Documentation/config/alias.txt +++ b/Documentation/config/alias.txt @@ -27,3 +27,24 @@ 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]. +* If the shell alias is the full path to a binary, it will be executed + directly with any arguments. +* If the alias contains any whitespace or reserved characters, it will + be considered an inline script and run as an argument to `sh -c`. +* When running as a script, Git appends "$@" to the alias shell + command when arguments are present. If there are no arguments, + `"$@"` will not be appended. +** This may initially be confusing if your alias script references + argument variables, or is otherwise not expecting the presence of + `"$@"`. For example: `alias.echo = "!echo $1"` when run as `git + echo arg` will actually execute `sh -c "echo $1 $@" "echo $1" + "arg"` resulting in output `arg arg`. An alias `alias.for = "!for + i in 1 2 3; do echo $i; done"` will fail if any arguments are + specified to `git for` as the appended `"$@"` will create invalid + shell syntax. +** 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.echo = "!e() { + echo $* ; }; e" will work as expected, with the function `e` + receiving any arugments from the command-line. +** Setting `GIT_TRACE=1` can help debug the command being run.