232 lines
6.9 KiB
Markdown
232 lines
6.9 KiB
Markdown
---
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title: Fish shell
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category: CLI
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layout: 2017/sheet
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prism_languages: [fish]
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updated: 2018-01-31
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weight: -1
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---
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### Keys
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| Shortcut | Description |
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| --- | --- |
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| `^A ←` _/_ `^E →` | Move to line beginning/end |
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| `Alt ←` _/_ `Alt →` | Move word |
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| `^U` | Delete to beginning |
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| `^W` | Delete to previous `/` |
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| `^D` | Delete next character |
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| `Alt D` | Delete next word |
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| `^C` | Cancel line |
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| `Alt P` | Page output |
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| --- | --- |
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| `Alt ↑` _/_ `Alt ↓` | Previous _/_ next arguments |
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| `Alt E` _/_ `Alt V` | Open in external editor |
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| `^L` | Repaint screen |
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{: .-shortcuts}
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### Help
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| `Alt H` | Help on word (man) |
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| `Alt W` | Help on word (short descriptions) |
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| `Alt L` | List directory on cursor |
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{: .-shortcuts}
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## Variables
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### Defining and erasing
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```fish
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set my_variable "Hello from Fish!"
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```
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```fish
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set --erase my_variable
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```
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### Incrementing and decrementing
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```fish
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set my_variable (math $my_variable + 1)
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set my_variable (math $my_variable - 1)
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```
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### Slicing
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```fish
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set my_variable $another_variable[1..10]
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set my_variable $another_variable[2..]
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set my_variable $another_variable[..-2]
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```
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## Arithmetic
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```fish
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math 1 + 2
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```
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| Operator | Performs |
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| --- | --- |
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| `+` | Addition |
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| `-` | Subtraction |
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| `*` | Multiplication |
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| `/` | Division |
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| `%` | Modulo |
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| `^` | Exponentiation |
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{: .-shortcuts}
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## String manipulation
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```fish
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string match --regex --entire 'Fish' 'Hello from Fish!'
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```
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```fish
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string replace --regex 'Fish' 'fish' 'Hello from Fish!'
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```
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| Pattern | Matches |
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| --- | --- |
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| `x?` | Zero or one `x` chars |
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| `x*` | Any count `x` chars |
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| `x+` | One or more `x` chars |
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| `x{n}` | n times `x` chars |
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| `x{n,m}` | n to m times `x` chars |
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| `x{n,}` | n or more times `x` chars |
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| `x{n,}` | n or more times `x` chars |
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| `[xy] ` | `x` or y char |
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| `[^xy]` | not `x` or y char |
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{: .-shortcuts}
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| Class | Description |
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| --- | --- |
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| `\w` | Word character |
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| `\d` | Digit character |
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| `\W` | Not word character |
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| `\D` | Not digit character |
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{: .-shortcuts}
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### Conditionals
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```fish
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if test $my_variable -lt $another_variable
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···
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else if test $my_variable -eq $another_variable
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···
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else
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···
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end
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```
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| Operator | Meaning |
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| --- | --- |
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| `-lt` | [L]ess [t]han |
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| `-eq` | [Eq]ual |
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| `-gt` | [G]reater [t]han |
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| `-le` | [L]ess than or [e]qual to |
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| `-ge` | [G]reater than or [e]qual to |
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| `-f` | [F]ile exists |
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| `-d` | [D]irectory exists |
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| `-r` | File or directory exists and [r]eadable |
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| `-w` | File or directory exists and [w]ritable |
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| `-x` | File or directory exists and e[x]ecutable |
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{: .-shortcuts}
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## Loops
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```fish
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for i in (seq 1 10)
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...
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end
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```
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## Command substitution
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```fish
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set my_variable (math $my_variable + 1)
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```
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## Functions
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### Defining and erasing
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```fish
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function my_function --description "My description"
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···
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end
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```
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```fish
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functions --erase my_function
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```
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### Event handling
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```fish
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function my_hook --on-event my_event
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···
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end
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```
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## Events
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### Emitting
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```fish
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emit my_event
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```
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## Abbreviations
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### Defining and erasing
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```fish
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abbr --add my_abbreviation echo "Hello from Fish!"
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```
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```fish
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abbr --erase my_abbreviation
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```
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## Completions
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### Defining and erasing
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```fish
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complete --command mycommand --arguments 'install uninstall'
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complete --command mycommand --short-option 'h' --long-option 'help' --description 'Display help'
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```
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```fish
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complete --command mycommand --erase
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```
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| Option | Description |
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| --- | --- |
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| `--arguments` | Arguments to command itself or option |
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| `--short-option` | Short option |
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| `--long-option` | Long option |
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| `--no-files` | Don't suggest files |
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| `--force-files` | Suggest files |
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| `--condition` | Display hint only when condition is true |
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| `--description` | Description |
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{: .-shortcuts}
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## Useful built-in functions
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| Condition | Description
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| --- | ---
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| `-n __fish_complete_directories STRING DESCRIPTION` | performs path completion on STRING, allowing only directories, and giving them the description DESCRIPTION.
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| `-n __fish_complete_path STRING DESCRIPTION` | performs path completion on STRING, giving them the description DESCRIPTION.
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| `-n __fish_complete_groups` | prints a list of all user groups with the groups members as description.
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| `-n __fish_complete_pids` | prints a list of all processes IDs with the command name as description.
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| `-n __fish_complete_suffix SUFFIX` | performs file completion allowing only files ending in SUFFIX. The mimetype database is used to find a suitable description.
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| `-n __fish_complete_users` | prints a list of all users with their full name as description.
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| `-n __fish_print_filesystems` | prints a list of all known file systems. Currently, this is a static list, and not dependent on what file systems the host operating system actually understands.
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| `-n __fish_print_hostnames` | prints a list of all known hostnames. This functions searches the fstab for nfs servers, ssh for known hosts and checks the /etc/hosts file.
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| `-n __fish_print_interfaces` | prints a list of all known network interfaces.
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| `-n __fish_print_packages` | prints a list of all installed packages. This function currently handles Debian, rpm and Gentoo packages.
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| `-n __fish_use_subcommand` |
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| `-n __fish_seen_subcommand_from init` |
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