{"id":140747,"date":"2018-01-31T11:00:52","date_gmt":"2018-01-31T16:00:52","guid":{"rendered":"https:\/\/spin.aa8q45el-liquidwebsites.com\/?p=140747"},"modified":"2018-03-28T13:21:11","modified_gmt":"2018-03-28T17:21:11","slug":"fish-shell-functions","status":"publish","type":"post","link":"https:\/\/spin.atomicobject.com\/fish-shell-functions\/","title":{"rendered":"Centralize Your Command Line with fish shell Functions"},"content":{"rendered":"

Developers use a lot of customizable tools, and it’s easy to reason through most of them. While text editors and IDEs come with config files and community standards for customizations, Unix-like shells can feel barren in comparison. However, fish shell<\/a> acts as a highly configurable alternative to other shells. <\/p>\n

(If you’re interested in switching to fish shell, my colleague John can show you how to set it up and use its coolest features<\/a>.)<\/p>\n

The unique part of the fish shell is the way it uses functions to decrease the reliance on monolithic config files. The separation of components into smaller, focused routines is a job that developers do every day.<\/p>\n

Functions<\/h2>\n

A fish function is a list of commands, which may optionally take arguments.<\/p><\/blockquote>\n

Functions are by far the best reason to try out the fish shell. If you’re like me, you have a bin<\/code> directory that acts as a catch-all in your $HOME<\/code> directory. Mine was cluttered with scripts that weren’t really binaries. I struggled to remember whether a command was aliased in my .profile<\/code> or sitting in bin<\/code>.<\/p>\n

The fish shell does away with both of these problems. For the first issue, all functions live in your home directory under ~\/.config\/fish\/functions<\/code>. They’re automatically loaded to the list of functions you can access from the fish shell, so there’s no need to add the directory to the path yourself.<\/p>\n

Aliases are available in fish, but they’re not recommended for creating functions. The functions directory adds a central location to list wrapped commands. While the alias<\/code> command still exists in fish, it’s just as easy to create a function file as it is to alias it in the fish config.<\/p>\n

An example of a quick override is the fish_greeting<\/code>. This is presented whenever you start a new shell session. One easy way to override or suppress it is by adding a fish_greeting.fish<\/code> file to your functions directory. Anything inside the fish_greeting function will now be shown in a new session.<\/p>\n

With the greeting modified, it would be a great time to modify fish’s prompt too. But there’s one caveat coming from Z Shell or Bash. There is no PS1 variable.<\/p>\n

Prompt<\/h2>\n

\"Fish
fish shell with default prompt<\/figcaption><\/figure><\/p>\n

You may notice that fish doesn’t provide a way to customize the command prompt via the PS1 variable. Instead, it executes the fish_prompt<\/code> function, which can be used to print a prompt. While the prompt defaults to showing the hostname and the current working directory, it can be changed to anything. A simple solution is to print the current working directory followed by a greater-than sign:<\/p>\n

function fish_prompt\r\n    printf ' '(prompt_pwd)'> '\r\nend<\/code><\/pre>\n
There are a few fish-specific features to explain in the code. The first is that the custom fish_prompt will override the default fish_prompt, just like fish_greeting did. Next, the parentheses around prompt_pwd represent command substitution. Finally, the result of prompt_pwd is a string, so fish can interpolate it into the first parameter of printf.<\/p>\n
\"Fish
fish shell with customized prompt<\/figcaption><\/figure><\/p>\n
These are just a few of the ways you can centralize your command-line workflow with fish. Functions replace simple shell scripts, overrides are straightforward, and everything can be found reasonably under the fish config directory. It’s a great way to streamline shell modifications.<\/p>\n
For further reading, try out the official fish documentation<\/a>. There’s an impressive amount of information for current fish users and those looking to dive into a new experience.<\/p>\n","protected":false},"excerpt":{"rendered":"
Developers use a lot of customizable tools, and it’s easy to reason through most of them. While text editors and IDEs come with config files and community standards for customizations, Unix-like shells can feel barren in comparison. However, fish shell acts as a highly configurable alternative to other shells.<\/p>\n","protected":false},"author":543,"featured_media":140772,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1731],"tags":[736,1006,2457],"series":[],"class_list":["post-140747","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-developer-tools","tag-terminal","tag-bash","tag-fish"],"acf":[],"yoast_head":"\nfish shell Functions \u2013 Centralize Your Command-Line<\/title>\n<meta name=\"description\" content=\"fish shell uses functions to decrease the reliance on a monolithic config file. 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