FISH(1) fish-shell FISH(1)

fish - the friendly interactive shell

fish [OPTIONS] [FILE [ARG ...]]
fish [OPTIONS] [-c COMMAND [ARG ...]]

fish is a command-line shell written mainly with interactive use in mind. This page briefly describes the options for invoking fish. The full manual <#intro> is available in HTML by using the help command from inside fish, and in the fish-doc(1) man page. The tutorial <> is available as HTML via help tutorial or in man fish-tutorial.

The following options are available:

Evaluate the specified commands instead of reading from the commandline. Any additional positional arguments are used as $argv.
Evaluate specified commands after reading the configuration but before executing command specified by -c or reading interactive input.
Enables debug output and specify a pattern for matching debug categories. See Debugging below for details.
Specifies a file path to receive the debug output, including categories and fish_trace <#envvar-fish_trace>. The default is standard error.
The shell is interactive.
Act as if invoked as a login shell.
Do not read configuration files.
Do not execute any commands, only perform syntax checking.
when fish exits, output timing information on all executed commands to the specified file. This excludes time spent starting up and reading the configuration.
Will write timing for fish startup to specified file.
Enables private mode <#private-mode>: fish will not access old or store new history.
When fish exits, output stats from getrusage.
Print all debug categories, and then exit.
Print version and exit.
Enables one or more comma-separated feature flags <#featureflags>.

The fish exit status is generally the exit status of the last foreground command <#variables-status>.

While fish provides extensive support for debugging fish scripts <#debugging>, it is also possible to debug and instrument its internals. Debugging can be enabled by passing the --debug option. For example, the following command turns on debugging for background IO thread events, in addition to the default categories, i.e. debug, error, warning, and warning-path:

> fish --debug=iothread

Available categories are listed by fish --print-debug-categories. The --debug option accepts a comma-separated list of categories, and supports glob syntax. The following command turns on debugging for complete, history, history-file, and profile-history, as well as the default categories:

> fish --debug='complete,*history*'

Debug messages output to stderr by default. Note that if fish_trace <#envvar-fish_trace> is set, execution tracing also outputs to stderr by default. You can output to a file using the --debug-output option:

> fish --debug='complete,*history*' --debug-output=/tmp/fish.log --init-command='set fish_trace on'

These options can also be changed via the FISH_DEBUG <#envvar-FISH_DEBUG> and FISH_DEBUG_OUTPUT <#envvar-FISH_DEBUG_OUTPUT> variables. The categories enabled via --debug are added to the ones enabled by $FISH_DEBUG, so they can be disabled by prefixing them with - (reader-*,-ast* enables reader debugging and disables ast debugging).

The file given in --debug-output takes precedence over the file in FISH_DEBUG_OUTPUT <#envvar-FISH_DEBUG_OUTPUT>.

To just start fish:

fish

To run a file with fish:

fish /path/to/script.fish

To run some commands with fish:

fish -c 'echo Hi there!'

You can also pass arguments to those commands:

> fish -c 'printf %s\n $argv' "first line" "second line"
first line
second line

To run a script, except read this other file first:

fish --init-cmd "source otherfile" script.fish

To profile <#profiling> fish's startup and find what takes the most time in your configuration:

fish --profile-startup /tmp/start.prof -ic exit
sort -nk2 /tmp/start.prof

fish-shell developers

November 14, 2025 4.2