Скачать или смотреть How to Properly Use alias in Fish Shell: Understanding Function Arguments

Discover why the `alias` command in Fish shell doesn't work the way you expect and learn the best practices for managing function arguments with a simple solution.
---
This video is based on the question https://stackoverflow.com/q/64380995/ asked by the user 'ShankarSwamy' ( https://stackoverflow.com/u/11433463/ ) and on the answer https://stackoverflow.com/a/64382006/ provided by the user 'Kurtis Rader' ( https://stackoverflow.com/u/4276647/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Forcing the order of arguments in function generated for a "alias"

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Challenge with alias in Fish Shell

If you’ve spent any time working with the Fish Shell, you may have stumbled upon the alias command. Designed to help streamline your command line usage, the alias feature can sometimes lead to confusion, especially when it comes to argument handling.

The core problem arises when you try to create an alias that requires tailored arguments. For instance, when you define an alias in the Fish Shell like this:

[[See Video to Reveal this Text or Code Snippet]]

You might expect that running myA 1234 would execute as PREFIX 1234 SUFFIX. Unfortunately, that is not the case. Instead, the command generates a function with a body that merely concatenates the specified strings and ignores your provided arguments.

Let’s dive into the solution to clarify how you can effectively manage this issue using Fish Shell.

Why Doesn't alias Work the Way You Expect?

First, it’s essential to understand how the Fish Shell processes aliases:

Interpolation: When you create an alias, any references to $argv are evaluated at the time of alias creation. This means if $argv is empty or undefined at that moment, then the command is simplified to just PREFIX SUFFIX with no passing parameters.

Misconception: This is particularly deceptive for those migrating from other shells, like Bash, where alias behaves differently.

A Better Approach Using Functions

To truly achieve your goal of passing dynamic arguments to PREFIX and SUFFIX, the solution lies not in using alias, but in defining a function. Here’s how you can manage that:

Step-by-Step Guide to Creating a Function

Function Definition: Instead of using alias, define a function that explicitly handles your arguments. Here’s the syntax you would use:

[[See Video to Reveal this Text or Code Snippet]]

Using the Function: Now, when you call myA 1234, it will correctly execute as PREFIX 1234 SUFFIX. The function captures the arguments as intended and allows for the flexible prefix and suffix.

Why Use Functions?

Flexibility: Functions in Fish Shell are versatile; they permit a practical way to manage command arguments without the issues that arise from using alias.

Clearer Syntax: As you develop further complex logic, writing functions can improve readability and maintainability in your scripts.

Conclusion

In closing, while the alias command may seem like a quick fix in Fish Shell for managing argument prefixes and suffixes, it is often misleading and insufficient. By employing function definitions, you can harness the full power of the shell, allowing for much more versatile and dynamic command usage. The next time you find yourself in a similar situation, remember that sometimes the simplest solutions can be the most effective.

Happy scripting! If you have any questions or would like to share your experiences with function handling in Fish Shell, feel free to leave a comment below!