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
1 file changed
+14
Documentation/config/alias.txt
+14
index 40851ef429..2c5db0ad84 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
+ added at the end. 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.