Keywords

Core language keywords that make up the syntax, like

• if and else for conditions.
• for and while for loops.
• break and continue to control loops.
• function to define functions.
• return to return a status from a function.
• begin to begin a block and end to end any block (including ifs and loops).
• and, or and not to combine commands logically.
• switch and case to make multiple blocks depending on the value of a variable.
• command or builtin to tell fish what sort of thing to execute
• time to time execution
• exec tells fish to replace itself with a command.
• end to end a block

Tools

Builtins to do a task, like

• cd to change the current directory.
• echo or printf to produce output.
• set_color to colorize output.
• set to set, query or erase variables.
• read to read input.
• string for string manipulation.
• path for filtering paths and handling their components.
• math does arithmetic.
• argparse to make arguments easier to handle.
• count to count arguments.
• type to find out what sort of thing (command, builtin or function) fish would call, or if it exists at all.
• test checks conditions like if a file exists or a string is empty.
• contains to see if a list contains an entry.
• eval and source to run fish code from a string or file.
• status to get shell information, like whether it’s interactive or a login shell, or which file it is currently running.
• abbr manages Abbreviations.
• bind to change bindings.
• complete manages completions.
• commandline to get or change the commandline contents.
• fish_config to easily change fish’s configuration, like the prompt or colorscheme.
• random to generate random numbers or pick from a list.

Known functions

Known functions are a customization point. You can change them to change how your fish behaves. This includes:

• fish_prompt and fish_right_prompt and fish_mode_prompt to print your prompt.
• fish_command_not_found to tell fish what to do when a command is not found.
• fish_title to change the terminal’s title.
• fish_tab_title to change the terminal tab’s title.
• fish_greeting to show a greeting when fish starts.
• fish_should_add_to_history to determine if a command should be added to history

Helper functions

Some helper functions, often to give you information for use in your prompt:

• fish_git_prompt and fish_hg_prompt to print information about the current git or mercurial repository.
• fish_vcs_prompt to print information for either.
• fish_svn_prompt to print information about the current svn repository.
• fish_status_to_signal to give a signal name from a return status.
• prompt_pwd to give the current directory in a nicely formatted and shortened way.
• prompt_login to describe the current login, with user and hostname, and to explain if you are in a chroot or connected via ssh.
• prompt_hostname to give the hostname, shortened for use in the prompt.
• fish_is_root_user to check if the current user is an administrator user like root.
• fish_add_path to easily add a path to $PATH.
• alias to quickly define wrapper functions (“aliases”).
• fish_delta to show what you have changed from the default configuration.
• export as a compatibility function for other shells.

Helper commands

fish also ships some things as external commands so they can be easily called from elsewhere.

This includes fish_indent to format fish code and fish_key_reader to show you what escape sequence a keypress produces.

The full list

And here is the full list:

• _ - call fish’s translations
• abbr - manage fish abbreviations
• alias - create a function
• and - conditionally execute a command
• argparse - parse options passed to a fish script or function
• begin - start a new block of code
• bg - send jobs to background
• bind - handle fish key bindings
• block - temporarily block delivery of events
• break - stop the current inner loop
• breakpoint - launch debug mode
• builtin - run a builtin command
• case - conditionally execute a block of commands
• cd - change directory
• cdh - change to a recently visited directory
• command - run a program
• commandline - set or get the current command line buffer
• complete - edit command-specific tab-completions
• contains - test if a word is present in a list
• continue - skip the remainder of the current iteration of the current inner loop
• count - count the number of elements of a list
• dirh - print directory history
• dirs - print directory stack
• disown - remove a process from the list of jobs
• echo - display a line of text
• else - execute command if a condition is not met
• emit - emit a generic event
• end - end a block of commands
• eval - evaluate the specified commands
• exec - execute command in current process
• exit - exit the shell
• export - compatibility function for exporting variables
• false - return an unsuccessful result
• fg - bring job to foreground
• fish - the friendly interactive shell
• fish_add_path - add to the path
• fish_breakpoint_prompt - define the prompt when stopped at a breakpoint
• fish_clipboard_copy - copy text to the system’s clipboard
• fish_clipboard_paste - get text from the system’s clipboard
• fish_command_not_found - what to do when a command wasn’t found
• fish_config - start the web-based configuration interface
• fish_default_key_bindings - set emacs key bindings for fish
• fish_delta - compare functions and completions to the default
• fish_git_prompt - output git information for use in a prompt
• fish_greeting - display a welcome message in interactive shells
• fish_hg_prompt - output Mercurial information for use in a prompt
• fish_indent - indenter and prettifier
• fish_is_root_user - check if the current user is root
• fish_key_reader - explore what characters keyboard keys send
• fish_mode_prompt - define the appearance of the mode indicator
• fish_opt - create an option specification for the argparse command
• fish_prompt - define the appearance of the command line prompt
• fish_right_prompt - define the appearance of the right-side command line prompt
• fish_should_add_to_history - decide whether a command should be added to the history
• fish_status_to_signal - convert exit codes to human-friendly signals
• fish_svn_prompt - output Subversion information for use in a prompt
• fish_tab_title - define the terminal tab’s title
• fish_title - define the terminal’s title
• fish_update_completions - update completions using manual pages
• fish_vcs_prompt - output version control system information for use in a prompt
• fish_vi_key_bindings - set vi key bindings for fish
• for - perform a set of commands multiple times
• funced - edit a function interactively
• funcsave - save the definition of a function to the user’s autoload directory
• function - create a function
• functions - print or erase functions
• help - display fish documentation
• history - show and manipulate command history
• if - conditionally execute a command
• isatty - test if a file descriptor is a terminal
• jobs - print currently running jobs
• math - perform mathematics calculations
• nextd - move forward through directory history
• not - negate the exit status of a job
• open - open file in its default application
• or - conditionally execute a command
• path - manipulate and check paths
• popd - move through directory stack
• prevd - move backward through directory history
• printf - display text according to a format string
• prompt_hostname - print the hostname, shortened for use in the prompt
• prompt_login - describe the login suitable for prompt
• prompt_pwd - print pwd suitable for prompt
• psub - perform process substitution
• pushd - push directory to directory stack
• pwd - output the current working directory
• random - generate random number
• read - read line of input into variables
• realpath - convert a path to an absolute path without symlinks
• return - stop the current inner function
• set - display and change shell variables
• set_color - set the terminal color
• source - evaluate contents of file
• status - query fish runtime information
• string - manipulate strings
• string-collect - join strings into one
• string-escape - escape special characters
• string-join - join strings with delimiter
• string-join0 - join strings with zero bytes
• string-length - print string lengths
• string-lower - convert strings to lowercase
• string-match - match substrings
• string-pad - pad strings to a fixed width
• string-repeat - multiply a string
• string-replace - replace substrings
• string-shorten - shorten strings to a width, with an ellipsis
• string-split - split strings by delimiter
• string-split0 - split on zero bytes
• string-sub - extract substrings
• string-trim - remove trailing whitespace
• string-unescape - expand escape sequences
• string-upper - convert strings to uppercase
• suspend - suspend the current shell
• switch - conditionally execute a block of commands
• test - perform tests on files and text
• time - measure how long a command or block takes
• trap - perform an action when the shell receives a signal
• true - return a successful result
• type - locate a command and describe its type
• ulimit - set or get resource usage limits
• umask - set or get the file creation mode mask
• vared - interactively edit the value of an environment variable
• wait - wait for jobs to complete
• while - perform a set of commands multiple times