fish-shell.md

   1 ---
   2 title: Fish shell
   3 category: CLI
   4 layout: 2017/sheet
   5 prism_languages: [fish]
   6 updated: 2018-01-31
   7 weight: -1
   8 ---
   9
  10 ### Keys
  11
  12 | Shortcut            | Description                 |
  13 | ---                 | ---                         |
  14 | `^A ←` _/_ `^E →`   | Move to line beginning/end  |
  15 | `Alt ←` _/_ `Alt →` | Move word                   |
  16 | `^U`                | Delete to beginning         |
  17 | `^W`                | Delete to previous `/`      |
  18 | `^D`                | Delete next character       |
  19 | `Alt D`             | Delete next word            |
  20 | `^C`                | Cancel line                 |
  21 | `Alt P`             | Page output                 |
  22 | ---                 | ---                         |
  23 | `Alt ↑` _/_ `Alt ↓` | Previous _/_ next arguments |
  24 | `Alt E` _/_ `Alt V` | Open in external editor     |
  25 | `^L`                | Repaint screen              |
  26 {: .-shortcuts}
  27
  28 ### Help
  29
  30 | `Alt H` | Help on word (man)                     |
  31 | `Alt W` | Help on word (short descriptions)      |
  32 | `Alt L` | List directory on cursor               |
  33 {: .-shortcuts}
  34
  35 ## Variables
  36
  37 ### Defining and erasing
  38
  39 ```fish
  40 set my_variable "Hello from Fish!"
  41 ```
  42
  43 ```fish
  44 set --erase my_variable
  45 ```
  46
  47 ### Incrementing and decrementing
  48
  49 ```fish
  50 set my_variable (math $my_variable + 1)
  51 set my_variable (math $my_variable - 1)
  52 ```
  53
  54 ### Slicing
  55
  56 ```fish
  57 set my_variable $another_variable[1..10]
  58 set my_variable $another_variable[2..]
  59 set my_variable $another_variable[..-2]
  60 ```
  61
  62 ## Arithmetic
  63
  64 ```fish
  65 math 1 + 2
  66 ```
  67
  68 | Operator            | Performs                    |
  69 | ---                 | ---                         |
  70 | `+`                 | Addition                    |
  71 | `-`                 | Subtraction                 |
  72 | `*`                 | Multiplication              |
  73 | `/`                 | Division                    |
  74 | `%`                 | Modulo                      |
  75 | `^`                 | Exponentiation              |
  76 {: .-shortcuts}
  77
  78 ## String manipulation
  79
  80 ```fish
  81 string match --regex --entire 'Fish' 'Hello from Fish!'
  82 ```
  83
  84 ```fish
  85 string replace --regex 'Fish' 'fish' 'Hello from Fish!'
  86 ```
  87
  88 | Pattern             | Matches                     |
  89 | ---                 | ---                         |
  90 | `x?`                | Zero or one `x` chars       |
  91 | `x*`                | Any count `x` chars         |
  92 | `x+`                | One or more  `x` chars      |
  93 | `x{n}`              | n times `x` chars           |
  94 | `x{n,m}`            | n to m times `x` chars      |
  95 | `x{n,}`             | n or more times `x` chars   |
  96 | `x{n,}`             | n or more times `x` chars   |
  97 | `[xy] `             | `x` or y char               |
  98 | `[^xy]`             | not `x` or y char           |
  99 {: .-shortcuts}
 100
 101 | Class               | Description                 |
 102 | ---                 | ---                         |
 103 | `\w`                | Word character              |
 104 | `\d`                | Digit character             |
 105 | `\W`                | Not word character          |
 106 | `\D`                | Not digit character         |
 107 {: .-shortcuts}
 108
 109 ### Conditionals
 110
 111 ```fish
 112 if test $my_variable -lt $another_variable
 113   ···
 114 else if test $my_variable -eq $another_variable
 115   ···
 116 else
 117   ···
 118 end
 119 ```
 120
 121 | Operator            | Meaning                                   |
 122 | ---                 | ---                                       |
 123 | `-lt`               | [L]ess [t]han                             |
 124 | `-eq`               | [Eq]ual                                   |
 125 | `-gt`               | [G]reater [t]han                          |
 126 | `-le`               | [L]ess than or [e]qual to                 |
 127 | `-ge`               | [G]reater than or [e]qual to              |
 128 | `-f`                | [F]ile exists                             |
 129 | `-d`                | [D]irectory exists                        |
 130 | `-r`                | File or directory exists and [r]eadable   |
 131 | `-w`                | File or directory exists and [w]ritable   |
 132 | `-x`                | File or directory exists and e[x]ecutable |
 133 {: .-shortcuts}
 134
 135 ## Loops
 136
 137 ```fish
 138 for i in (seq 1 10)
 139   ...
 140 end
 141 ```
 142
 143 ## Command substitution
 144
 145 ```fish
 146 set my_variable (math $my_variable + 1)
 147 ```
 148
 149 ## Functions
 150
 151 ### Defining and erasing
 152
 153 ```fish
 154 function my_function --description "My description"
 155   ···
 156 end
 157 ```
 158
 159 ```fish
 160 functions --erase my_function
 161 ```
 162
 163 ### Event handling
 164
 165 ```fish
 166 function my_hook --on-event my_event
 167   ···
 168 end
 169 ```
 170
 171 ## Events
 172
 173 ### Emitting
 174
 175 ```fish
 176 emit my_event
 177 ```
 178
 179
 180 ## Abbreviations
 181
 182 ### Defining and erasing
 183
 184 ```fish
 185 abbr --add my_abbreviation echo "Hello from Fish!"
 186 ```
 187
 188 ```fish
 189 abbr --erase my_abbreviation
 190 ```
 191
 192 ## Completions
 193
 194 ### Defining and erasing
 195
 196 ```fish
 197 complete --command mycommand --arguments 'install uninstall'
 198 complete --command mycommand --short-option 'h' --long-option 'help' --description 'Display help'
 199 ```
 200
 201 ```fish
 202 complete --command mycommand --erase
 203 ```
 204
 205 | Option              | Description                               |
 206 | ---                 | ---                                       |
 207 | `--arguments`       | Arguments to command itself or option     |
 208 | `--short-option`    | Short option                              |
 209 | `--long-option`     | Long option                               |
 210 | `--no-files`        | Don't suggest files                       |
 211 | `--force-files`     | Suggest files                             |
 212 | `--condition`       | Display hint only when condition is true  |
 213 | `--description`     | Description                               |
 214 {: .-shortcuts}
 215
 216 ## Useful built-in functions
 217
 218 | Condition | Description
 219 | --- | ---
 220 | `-n __fish_complete_directories STRING DESCRIPTION` | performs path completion on STRING, allowing only directories, and giving them the description DESCRIPTION.
 221 | `-n __fish_complete_path STRING DESCRIPTION` | performs path completion on STRING, giving them the description DESCRIPTION.
 222 | `-n __fish_complete_groups` | prints a list of all user groups with the groups members as description.
 223 | `-n __fish_complete_pids` | prints a list of all processes IDs with the command name as description.
 224 | `-n __fish_complete_suffix SUFFIX` | performs file completion allowing only files ending in SUFFIX. The mimetype database is used to find a suitable description.
 225 | `-n __fish_complete_users` | prints a list of all users with their full name as description.
 226 | `-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.
 227 | `-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.
 228 | `-n __fish_print_interfaces` | prints a list of all known network interfaces.
 229 | `-n __fish_print_packages` | prints a list of all installed packages. This function currently handles Debian, rpm and Gentoo packages.
 230 | `-n __fish_use_subcommand` |
 231 | `-n __fish_seen_subcommand_from init` |