fish(1)

Quick Info

Fish initialization file ~/.config/fish/config.fish

Switch between different key bindings:

fish_default_key_bindings to use default key bindings
fish_vi_key_bindings to use vi key bindings

Variables

Available scopes

local variable local to a block
global variable global to shell instance
universal variable universal to all shell instances + preserved across +shell restart

Set/Unset Variables

set <name> [<values>]
+    -l  local scope
+    -g  global scope
+    -U  universal scope
+    -e  erase variable
+    -S  show verbose info
+    -x  export to ENV
+    -u  unexport from ENV
+

Lists

In fish all variables are lists (start with index 1, but lists can't +contain lists.

set foo a b c d
+
+echo $foo[1]      # a
+echo $foo[-1]     # d
+echo $foo[2..3]   # b c
+echo $foo[1 3]    # a c
+

$ can be seen as dereference operator.

set foo a; set a 1337
+echo $$foo  # outputs 1337
+

Cartesian product.

echo file.{h,cc}
+# file.h file.cc
+
+echo {a,b}{1,2}
+# a1 b1 b2
+

Special Variables (Lists)

$status      # exit code of last command
+$pipestatus  # list of exit codes of pipe chain
+
+$CMD_DURATION   # runtime of last command in ms
+

`*PATH`

Lists ending with PATH are automatically split at : when used and joined +with : when exported to the environment.

set -x BLA_PATH a:b:c:d
+echo $BLA_PATH              # a b c d
+env | grep BLA_PATH         # BLA_PATH=a:b:c:d
+

Command Handling

# sub-commands are not run in quotes
+echo "ls output: "(ls)
+

I/O redirection

# 'noclobber', fail if 'log' already exists
+echo foo >? log
+

Control Flow

`if` / `else`

if grep foo bar
+    # do sth
+else if grep foobar bar
+    # do sth else
+else
+    # do sth else
+end
+

`switch`

switch (echo foo)
+case 'foo*'
+    # do start with foo
+case bar dudel
+    # do bar and dudel
+case '*'
+    # do else
+end
+

`while` Loop

while true
+    echo foo
+end
+

`for` Loop

for f in (ls)
+    echo $f
+end
+

Functions

Function arguments are passed via $argv list.

function fn_foo
+    echo $argv
+end
+

Autoloading

When running a command fish attempts to autoload a function. The shell looks +for <cmd>.fish in the locations defined by $fish_function_path and loads +the function lazily if found.

This is the preferred way over monolithically defining all functions in a +startup script.

Helper

functions         # list al functions
+functions foo     # describe function 'foo'
+functions -e foo  # erase function 'foo'
+
+funced foo        # edit function 'foo'
+                  # '-e vim' to edit in vim
+

Prompt

The prompt is defined by the output of the fish_prompt function.

function fish_prompt
+    set -l cmd_ret
+    echo "> "(pwd) $cmd_ret" "
+end
+

+
Use set_color to manipulate terminal colors.
+

Useful Builtins

# history
+history search <str>   # search history for <str>
+history merge          # merge histories from fish sessions
+
+# list
+count $var            # count elements in list
+
+# string
+string split SEP STRING
+

Keymaps

  Shift-Tab ........... tab-completion with search
+  Alt-Up / Alt-Down ... search history with token under the cursor
+  Alt-l ............... list content of dir under cursor
+  Alt-p ............... append '2>&1 | less;' to current cmdline
+

Debug

  status print-stack-trace .. prints function stacktrace (can be used in scripts)
+  breakpoint ................ halt script execution and gives shell (C-d | exit
+                              to continue)
+

+ +

Notes