fish 3 is a major release, which introduces some breaking changes alongside improved functionality. Although most existing scripts will continue to work, they should be reviewed against the list below.

To download the source code for fish, we suggest the file named "fish-3.0b1.tar.gz". The file downloaded from "Source code (tar.gz)" will not build correctly. The SHA-256 sum of this file is 11c464ac9f2b838b0a9e3fb8e91f7727649d0d13122b5bcb7bc4e5199bc5e8a6. A GPG signature from David Adam (0x7A67D962D88A709A) is available as "fish-3.0b1.tar.gz.asc".

Notable non-backward compatible changes

• Process and job expansion has largely been removed. % will no longer perform these expansions, except for %self for the PID of the current shell. Additionally, job management commands (disown, wait, bg, fg and kill) will expand job specifiers starting with % (#4230, #1202).
• set x[1] x[2] a b, to set multiple elements of an array at once, is no longer valid syntax (#4236).
• A literal {} now expands to itself, rather than nothing. This makes working with find -exec easier (#1109, #4632).
• Literally accessing a zero-index is now illegal syntax and is caught by the parser (#4862). (fish indices start at 1)
• Successive commas in brace expansions are handled in less surprising manner. For example, {,,,} expands to four empty strings rather than an empty string, a comma and an empty string again (#3002, #4632).
• for loop control variables are no longer local to the for block (#1935).
• Variables set in if and while conditions are available outside the block (#4820).
• Local exported (set -lx) vars are now visible to functions (#1091).
• The new math builtin (see below) does not support logical expressions; test should be used instead (#4777).
• Range expansion will now behave sensibly when given a single positive and negative index ($foo[5..-1] or $foo[-1..5]), clamping to the last valid index without changing direction if the list has fewer elements than expected.
• read now uses -s as short for --silent (à la bash); --shell's abbreviation (formerly -s) is now -S instead (#4490).
• cd no longer resolves symlinks. fish now maintains a virtual path, matching other shells (#3350).
• source now requires an explicit - as the filename to read from the terminal (#2633).
• Arguments to end are now errors, instead of being silently ignored.
• The names argparse, read, set, status, test and [ are now reserved and not allowed as function names. This prevents users unintentionally breaking stuff (#3000).
• The fish_user_abbreviations variable is no longer used; abbreviations will be migrated to the new storage format automatically.
• The FISH_READ_BYTE_LIMIT variable is now called fish_byte_limit (#4414).
• Environment variables are no longer split into arrays based on the record separator character on startup. Instead, variables are not split, unless their name ends in PATH, in which case they are split on colons (#436).
• The history builtin's --with-time option has been removed; this has been deprecated in favor of --show-time since 2.7.0 (#4403).
• The internal variables __fish_datadir and __fish_sysconfdir are now known as __fish_data_dir and __fish_sysconf_dir respectively.

Deprecations

With the release of fish 3, a number of features have been marked for removal in the future. All users are encouraged to explore alternatives. A small number of these features are currently behind feature flags, which are turned on at present but may be turned off by default in the future.

A new feature flags mechanism is added for staging deprecations and breaking changes. Feature flags may be specified at launch with fish --features ... or by setting the universal fish_features variable. (#4940)

• The use of the IFS variable for read is deprecated; IFS will be ignored in the future (#4156). Use the read --delimiter option instead.
• The function --on-process-exit switch will be removed in future (#4700). Use the fish_exit event instead: function --on-event fish_exit.
• $_ is deprecated and will removed in the future (#813). Use status current-command in a command substitution instead.
• ^ as a redirection deprecated and will be removed in the future. (#4394). Use 2> to redirect stderr. This is controlled by the stderr-nocaret feature flag.
• ? as a glob (wildcard) is deprecated and will be removed in the future (#4520). This is controlled by the qmark-noglob feature flag.

Notable fixes and improvements

Syntax changes and new commands

• fish now supports && (like and), || (like or), and ! (like not), for better migration from POSIX-compliant shells (#4620).
• Variables may be used as commands (#154).
• fish may be started in private mode via fish --private. Private mode fish sessions do not have access to the history file and any commands evaluated in private mode are not persisted for future sessions. A session variable $fish_private_mode can be queried to detect private mode and adjust the behavior of scripts accordingly to respect the user's wish for privacy.
• A new wait command for waiting on backgrounded processes (#4498).
• math is now a builtin rather than a wrapper around bc (#3157). Floating point computations is now used by default, and can be controlled with the new --scale option (#4478).
• Setting $PATH no longer warns on non-existent directories, allowing for a single $PATH to be shared across machines (eg via dotfiles) (#2969).
• while sets $status to a non-zero value if the loop is not executed (#4982).
• Command substitution output is now limited to 10 MB by default, controlled by the fish_read_limit variable (#3822). Notably, this is larger than most operating systems' argument size limit, so trying to pass argument lists this size to external commands has never worked.
• The machine hostname, where available, is now exposed as the $hostname reserved variable. This removes the dependency on the hostname executable (#4422).
• Bare bind invocations in config.fish now work. The fish_user_key_bindings function is no longer necessary, but will still be executed if it exists (#5191).
• $fish_pid and $last_pid are available as replacements for %self and %last.

New features in commands

• alias has a new --save option to save the generated function immediately (#4878).
• bind has a new --silent option to ignore bind requests for named keys not available under the current terminal (#4188, #4431).
• complete has a new --keep-order option to show the provided or dynamically-generated argument list in the same order as specified, rather than alphabetically (#361).
• exec prompts for confirmation if background jobs are running.
• funced has a new --save option to automatically save the edited function after successfully editing (#4668).
• functions has a new --handlers option to show functions registered as event handlers (#4694).
• history search supports globs for wildcard searching (#3136) and has a new --reverse option to show entries from oldest to newest (#4375)..
• jobs has a new --quiet option to silence the output.
• read has a new --delimiter option for splitting input into arrays (#4256).
• read writes directly to stdout if called without arguments (#4407).
• read can now read individual lines into separate variables without consuming the input in its entirety via the new /--line option.
• set has new --append and --prepend options (#1326).
• set has a new --show option to show lots of information about variables (#4265).
• string match with an empty pattern and --entire in glob mode now matches everything instead of nothing (#4971).
• string split supports a new --no-empty option to exclude empty strings from the result (#4779).
• string has new subcommands split0 and join0 for working with NUL-delimited output.
• string no longer stops processing text after NUL characters (#4605)
• string escape has a new --style regex option for escaping strings to be matched literally in string regex operations.
• test now supports floating point values in numeric comparisons.

Interactive improvements

• A pipe at the end of a line now allows the job to continue on the next line (#1285).
• Italics and dim support out of the box on macOS for Terminal.app and iTerm (#4436).
• cd tab completions no longer descend into the deepest unambiguous path (#4649).
• Pager navigation has been improved. Most notably, moving down now wraps around, moving up from the commandline now jumps to the last element and moving right and left now reverse each other even when wrapping around (#4680).
• Typing normal characters while the completion pager is active no longer shows the search field. Instead it enters them into the command line, and ends paging (#2249).
• A new input binding pager-toggle-search toggles the search field in the completions pager on and off. By default, this is bound to Ctrl-S.
• Searching in the pager now does a full fuzzy search (#5213).
• The pager will now show the full command instead of just its last line if the number of completions is large (#4702).
• Abbreviations can be tab-completed (#3233).
• Tildes in file names are now properly escaped in completions (#2274).
• Wrapping completions (from complete --wraps or function --wraps) can now inject arguments. For example, complete gco --wraps 'git checkout' now works properly (#1976). The alias function has been updated to respect this behavior.
• Path completions now support expansions, meaning expressions like python ~/<TAB> now provides file suggestions just like any other relative or absolute path. (This includes support for other expansions, too.)
• Autosuggestions try to avoid arguments that are already present in the command line.
• Notifications about crashed processes are now always shown, even in command substitutions (#4962).
• The screen is no longer reset after a BEL, fixing graphical glitches (#3693).
• vi-mode now supports ';' and ',' motions. This introduces new {forward,backward}-jump-till and repeat-jump{,-reverse} bind functions (#5140).
• The *y vi-mode binding now works (#5100).
• True color is now enabled in neovim by default (#2792).
• Terminal size variables ($COLUMNS/$LINES) are now updated before fish_prompt is called, allowing the prompt to react (#904).
• Multi-line prompts no longer repeat when the terminal is resized (#2320).
• xclip support has been added to the clipboard integration (#5020).
• The Alt-P keybinding paginates the last command if the command line is empty.
• $cmd_duration is no longer reset when no command is executed (#5011).
• Deleting a one-character word no longer erases the next word as well (#4747).
• Token history search (Alt-Up) omits duplicate entries (#4795).
• The fish_escape_delay_ms timeout, allowing the use of the escape key both on its own and as part of a control sequence, was applied to all control characters; this has been reduced to just the escape key.
• Completing a function shows the description properly (#5206).
• Added completions for
  • ansible, including ansible-galaxy, ansible-playbook and ansible-vault (#4697)
  • bb-power (#4800)
  • bd (#4472)
  • bower
  • clang and clang++ (#4174)
  • conda (#4837)
  • configure (for autoconf-generated files only)
  • curl
  • doas (#5196)
  • ebuild (#4911)
  • emaint (#4758)
  • eopkg (#4600)
  • exercism (#4495)
  • hjson
  • hugo (#4529)
  • j (from autojump #4344)
  • jbake (#4814)
  • jhipster (#4472)
  • kitty
  • kldload
  • kldunload
  • makensis (#5242)
  • meson
  • mkdocs (#4906)
  • ngrok (#4642)
  • OpenBSD's pkg_add, pkg_delete, pkg_info, pfctl, rcctl, signify, and vmctl (#4584)
  • openocd
  • optipng
  • opkg (#5168)
  • pandoc (#2937)
  • port (#4737)
  • powerpill (#4800)
  • pstack (#5135)
  • serve (#5026)
  • ttx
  • unzip
  • virsh (#5113)
  • xclip (#5126)
  • xsv
  • zfs and zpool (#4608)
• Lots of improvements to completions (especially darcs (#5112), git, hg and sudo).
• Completions for yarn and npm now require the all-the-package-names NPM package for full functionality.
• Completions for bower and yarn now require the jq utility for full functionality.
• Improved French translations.

Other fixes and improvements

• Significant performance improvements to abbr (#4048), setting variables (#4200, #4341), executing functions, globs (#4579), string reading from standard input (#4610), and slicing history (in particular, $history[1] for the last executed command).
• Fish's internal wcwidth function has been updated to deal with newer Unicode, and the width of some characters can be configured via the fish_ambiguous_width (#5149) and fish_emoji_width (#2652) variables. Alternatively, a new build-time option INTERNAL_WCWIDTH can be used to use the system's wcwidth instead (#4816).
• functions correctly supports -d as the short form of --description. (#5105)
• /etc/paths is now parsed like macOS' bash path_helper, fixing $PATH order (#4336, #4852) on macOS.
• Using a read-only variable in a for loop produces an error, rather than silently producing incorrect results (#4342).
• The universal variables filename no longer contains the hostname or MAC address. It is now at the fixed location .config/fish/fish_variables (#1912).
• Exported variables in the global or universal scope no longer have their exported status affected by local variables (#2611).
• Major rework of terminal and job handling to eliminate bugs (#3805, #3952, #4178, #4235, #4238, #4540, #4929, #5210).
• Improvements to the manual page completion generator (#2937, #4313).
• suspend --force now works correctly (#4672).
• Pressing Ctrl-C while running a script now reliably terminates fish (#5253).

For distributors and developers

• fish ships with a new build system based on CMake. CMake 3.2 is the minimum required version. Although the autotools-based Makefile and the Xcode project are still shipped with this release, they will be removed in the near future. All distributors and developers are encouraged to migrate to the CMake build.
• Build scripts for most platforms no longer require bash, using the standard sh instead.
• The hostname and bc commands are no longer required for fish to operate.