Documentation: alias: add notes on shell expansion
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> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Ian Wienand committed
May 27, 2024 at 10:30 UTC
d35a7436597277d65c84acdc4e951c45c791ea15
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Documentation/config/alias.txt
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@@ -27,3 +27,17 @@ it will be treated as a shell command. For example, defining
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repository, which may not necessarily be the current directory.
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* `GIT_PREFIX` is set as returned by running `git rev-parse --show-prefix`
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from the original current directory. See linkgit:git-rev-parse[1].
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+* Shell command aliases always receive any extra arguments provided to
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+ the Git command-line as positional arguments.
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+** Care should be taken if your shell alias is a "one-liner" script
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+ with multiple commands (e.g. in a pipeline), references multiple
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+ arguments, or is otherwise not able to handle positional arguments
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+ added at the end. For example: `alias.cmd = "!echo $1 | grep $2"`
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+ called as `git cmd 1 2` will be executed as 'echo $1 | grep $2
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+ 1 2', which is not what you want.
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+** A convenient way to deal with this is to write your script
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+ operations in an inline function that is then called with any
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+ arguments from the command-line. For example `alias.cmd = "!c() {
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+ echo $1 | grep $2 ; }; c" will correctly execute the prior example.
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+** Setting `GIT_TRACE=1` can help you debug the command being run for
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+ your alias.