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When defining a new function in fish, it's possible to make it into an event handler - a function that is automatically run when a specific event takes place.

*Note: event handler is a function, but a function isn't an event handler.

Events that can trigger a handler currently are:

• A signal is delivered
• A job exits
• The value of a variable is updated

Some noted event handlers

vhbui02

Here are some files/directories are run in the following order, that worth to note:

Configuration snippets (named *.fish)

• ~/.config/fish/conf.d/: fish local config dir
• /etc/fish/conf.d/: fish system config dir

If some softwares need specific configuration snippets, they can be put inside:

• $XDG_DATA_HOME/fish controlled by $XDG_DATA_HOME (default value is $HOME/.local/share)

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Autoloading = Lazy loading

When fish needs to load a function

It searches through any dirs in the list variable $fish_function_path, for a file with name that consists the func name + suffix .fish and loads the 1st file it finds (remember, 1st)

If you put multiple funcs in 1 file .fish

The file (whole file, not just 1 func) will ONLY be loaded when you execute a function with the same name as that file.

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Remember

• function: Create
• functions: Read and Delete
• funced: Update
• funcsave: Update (support), Delete (support)

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Some option that needs to be remembered

status: no arguments, simply display the current login and job control status of the Fish shell.

status is-login / --is-login / -l: return 0 if current Fish shell is a login shell

status is-interactive / --is-interactive / -i: return 0 if current Fish shell is interactive (connected to a keyboard)

status is-block / --is-block / -b: return 0 if fish is currently executing a block of code.

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Dirname

dirname [OPTION] NAME

Extract the path to get to the file called NAME (excluding the NAME itself).

Absolute path:

dirname /foo/bar/baz => /foo/bar (notice the / before foo is existed)

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type [OPTIONS] NAME

Option

-a or --all: prints exe, function (with definition expansion), and built-in.

-s or --short: suppresses function definition expansion.

-f or --no-function: suppresses function and built-in lookup.

-t or --type: prints the type currently working of command:

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Ampersand

2>1: redirect stderr to a file called 1 2>&1: redirect stderr to stdout

Note: 1 and 2 are called file descriptor.

Note 2: > and 1> are the same.

Redirect stdout and stderr to different locations

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List of files i've changed

D:\Development_Tools\Visual Paradigm CE 17.0\bin: Visual Paradigm.exe to vp.exe

/usr/share/fish/functions/__fish_anypython.fish: I've changed:

for py in python3 python3.{9,8,7,6,5,4,3} python2 python2.7 python

to

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local variable inside for body isn't exported to outside, remember to use set -x option.

Syntax

for <var-name> in $list_variable
	echo $<var-name>
end