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<a href="http://fishshell.com/"><code>fish</code> shell</a>
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<div class="title">Tutorial </div> </div>
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<ul>
<li><a href="#tut_why_fish">Why fish?</a></li>
<li><a href="#tut_learning_Fish">Learning fish</a></li>
<li><a href="#tut_running_commands">Running Commands</a></li>
<li><a href="#tut_getting_help">Getting Help</a></li>
<li><a href="#tut_syntax_highlighting">Syntax Highlighting</a></li>
<li><a href="#tut_wildcards">Wildcards</a></li>
<li><a href="#tut_pipes_and_redirections">Pipes and Redirections</a></li>
<li><a href="#tut_autosuggestions">Autosuggestions</a></li>
<li><a href="#tut_tab_completions">Tab Completions</a></li>
<li><a href="#tut_variables">Variables</a></li>
<li><a href="#tut_exit_status">Exit Status</a></li>
<li><a href="#tut_exports">Shell Variables</a></li>
<li><a href="#tut_lists">Lists</a></li>
<li><a href="#tut_command_substitutions">Command Substitutions</a></li>
<li><a href="#tut_combiners">Combiners (And, Or, Not)</a></li>
<li><a href="#tut_conditionals">Conditionals (If, Else, Switch)</a></li>
<li><a href="#tut_functions">Functions</a></li>
<li><a href="#tut_loops">Loops</a></li>
<li><a href="#tut_prompt">Prompt</a></li>
<li><a href="#tut_path">$PATH</a></li>
<li><a href="#tut_startup">Startup</a></li>
<li><a href="#tut_autoload">Autoloading Functions</a></li>
<li><a href="#tut_universal">Universal Variables</a></li>
<li><a href="#tut_more">Ready for more?</a></li>
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<h1 class="interior_title">fish tutorial</h1>
<h1><a class="anchor" id="tut_why_fish"></a>
Why fish?</h1>
<code>fish</code> is a fully-equipped command line shell (like bash or zsh) that is smart and user-friendly. <code>fish</code> supports powerful features like syntax highlighting, autosuggestions, and tab completions that just work, with nothing to learn or configure.
If you want to make your command line more productive, more useful, and more fun, without learning a bunch of arcane syntax and configuration options, then <code>fish</code> might be just what you're looking for!
<h1><a class="anchor" id="tut_learning_Fish"></a>
Learning fish</h1>
This tutorial assumes a basic understanding of command line shells and Unix commands, and that you have a working copy of <code>fish</code>.
If you have a strong understanding of other shells, and want to know what <code>fish</code> does differently, search for the magic phrase unlike other shells, which is used to call out important differences.
When you start <code>fish</code>, you should see this:
 
 <pre class="fish cli-dark">
Welcome to fish, the friendly interactive shell
Type help for instructions on how to use fish
you@hostname ~&gt; 
</pre><code>fish</code> comes with a default prompt that shows your username, hostname, and working directory. You'll see <a href="#tut_prompt">how to change your prompt</a> further down. From now on, we'll pretend your prompt is just a '<code>&gt;</code>' to save space.
<h1><a class="anchor" id="tut_running_commands"></a>
Running Commands</h1>
<code>fish</code> runs commands like other shells: you type a command, followed by its arguments. Spaces are separators:
 
 <pre class="fish cli-dark">
&gt; echo hello world
hello world
</pre>You can include a literal space in an argument with a backslash, or by using single or double quotes:
 
 <pre class="fish cli-dark">
&gt; mkdir My\ Files
&gt; cp ~/Some\ File 'My Files'
&gt; ls "My Files"
Some File
</pre>Commands can be chained with semicolons.
<h1><a class="anchor" id="tut_getting_help"></a>
Getting Help</h1>
<code>fish</code> has excellent help and man pages. Run <code>help</code> to open help in a web browser, and <code>man</code> to open it in a man page. You can also ask for help with a specific command, for example, <code>help set</code> to open in a web browser, or <code>man set</code> to see it in the terminal.
 
 <pre class="fish cli-dark">
&gt; man set
set - handle shell variables
 Synopsis...
</pre><h1><a class="anchor" id="tut_syntax_highlighting"></a>
Syntax Highlighting</h1>
You'll quickly notice that <code>fish</code> performs syntax highlighting as you type. Invalid commands are colored red by default:
 
 <pre class="fish cli-dark">
&gt; /bin/mkd
</pre>A command may be invalid because it does not exist, or refers to a file that you cannot execute. When the command becomes valid, it is shown in a different color:
 
 <pre class="fish cli-dark">
&gt; /bin/mkdir
</pre><code>fish</code> will underline valid file paths as you type them:
 
 <pre class="fish cli-dark">
&gt; cat ~/somefi 
</pre>This tells you that there exists a file that starts with '<code>somefi</code>', which is useful feedback as you type.
These colors, and many more, can be changed by running <code>fish_config</code>, or by modifying variables directly.
<h1><a class="anchor" id="tut_wildcards"></a>
Wildcards</h1>
<code>fish</code> supports the familiar wildcard <code>*</code>. To list all JPEG files:
 
 <pre class="fish cli-dark">
&gt; ls *.jpg
lena.jpg
meena.jpg
santa maria.jpg
</pre>You can include multiple wildcards:
 
 <pre class="fish cli-dark">
&gt; ls l*.p*
lena.png
lesson.pdf
</pre>Especially powerful is the recursive wildcard ** which searches directories recursively:
 
 <pre class="fish cli-dark">
&gt; ls /var/**.log
/var/log/system.log
/var/run/sntp.log
</pre>If that directory traversal is taking a long time, you can Control-C out of it.
<h1><a class="anchor" id="tut_pipes_and_redirections"></a>
Pipes and Redirections</h1>
You can pipe between commands with the usual vertical bar:
 
 <pre class="fish cli-dark">
&gt; echo hello world | wc
 1 2 12
</pre>stdin and stdout can be redirected via the familiar &lt; and &gt;. Unlike other shells, stderr is redirected with a caret ^
 
 <pre class="fish cli-dark">
&gt; grep fish &lt; /etc/shells &gt; ~/output.txt ^ ~/errors.txt
</pre><h1><a class="anchor" id="tut_autosuggestions"></a>
Autosuggestions</h1>
<code>fish</code> suggests commands as you type, and shows the suggestion to the right of the cursor, in gray. For example:
 
 <pre class="fish cli-dark">
&gt; /bin/hostname
</pre>It knows about paths and options:
 
 <pre class="fish cli-dark">
&gt; grep --ignore-case
</pre>And history too. Type a command once, and you can re-summon it by just typing a few letters:
 
 <pre class="fish cli-dark">
&gt; rsync -avze ssh . myname@somelonghost.com:/some/long/path/doo/dee/doo/dee/doo
</pre>To accept the autosuggestion, hit &rarr; or Control-F. To accept a single word of the autosuggestion, Alt-&rarr; (right arrow). If the autosuggestion is not what you want, just ignore it.
<h1><a class="anchor" id="tut_tab_completions"></a>
Tab Completions</h1>
<code>fish</code> comes with a rich set of tab completions, that work "out of the box."
Press Tab, and <code>fish</code> will attempt to complete the command, argument, or path:
 
 <pre class="fish cli-dark">
&gt; /pri @key{Tab} &rarr; /private/
</pre>If there's more than one possibility, it will list them:
 
 <pre class="fish cli-dark">
&gt; ~/stuff/s @key{Tab}
~/stuff/script.sh (Executable, 4.8kB) ~/stuff/sources/ (Directory)
</pre>Hit tab again to cycle through the possibilities.
<code>fish</code> can also complete many commands, like git branches:
 
 <pre class="fish cli-dark">
&gt; git merge pr @key{Tab} &rarr; git merge prompt_designer
&gt; git checkout b @key{Tab}
builtin_list_io_merge (Branch) builtin_set_color (Branch) busted_events (Tag)
</pre>Try hitting tab and see what <code>fish</code> can do!
<h1><a class="anchor" id="tut_variables"></a>
Variables</h1>
Like other shells, a dollar sign performs variable substitution:
 
 <pre class="fish cli-dark">
&gt; echo My home directory is $HOME
My home directory is /home/tutorial
</pre>Variable substitution also occurs in double quotes, but not single quotes:
 
 <pre class="fish cli-dark">
&gt; echo "My current directory is $PWD"
My current directory is /home/tutorial
&gt; echo 'My current directory is $PWD'
My current directory is $PWD
</pre>Unlike other shells, <code>fish</code> has no dedicated syntax for setting variables. Instead it has an ordinary command: <code>set</code>, which takes a variable name, and then its value.
 
 <pre class="fish cli-dark">
&gt; set name 'Mister Noodle'
&gt; echo $name
Mister Noodle
</pre>(Notice the quotes: without them, <code>Mister</code> and <code>Noodle</code> would have been separate arguments, and <code>$name</code> would have been made into a list of two elements.)
Unlike other shells, variables are not further split after substitution:
 
 <pre class="fish cli-dark">
&gt; mkdir $name
&gt; ls
Mister Noodle
</pre>In bash, this would have created two directories "Mister" and "Noodle". In <code>fish</code>, it created only one: the variable had the value "Mister Noodle", so that is the argument that was passed to <code>mkdir</code>, spaces and all. Other shells use the term "arrays", rather than lists.
<h1><a class="anchor" id="tut_exit_status"></a>
Exit Status</h1>
Unlike other shells, <code>fish</code> stores the exit status of the last command in <code>$status</code> instead of <code>$?</code>.
 
 <pre class="fish cli-dark">
&gt; false
&gt; echo $status
1
</pre>Zero is considered success, and non-zero is failure.
<h1><a class="anchor" id="tut_exports"></a>
Exports (Shell Variables)</h1>
Unlike other shells, <code>fish</code> does not have an export command. Instead, a variable is exported via an option to <code>set</code>, either <code>--export</code> or just <code>-x</code>.
 
 <pre class="fish cli-dark">
&gt; set -x MyVariable SomeValue
&gt; env | grep MyVariable
MyVariable=SomeValue
</pre>You can erase a variable with <code>-e</code> or <code>--erase</code>
 
 <pre class="fish cli-dark">
&gt; set -e MyVariable
&gt; env | grep MyVariable
(no output)
</pre><h1><a class="anchor" id="tut_lists"></a>
Lists</h1>
The <code>set</code> command above used quotes to ensure that <code>Mister Noodle</code> was one argument. If it had been two arguments, then <code>name</code> would have been a list of length 2. In fact, all variables in <code>fish</code> are really lists, that can contain any number of values, or none at all.
Some variables, like <code>$PWD</code>, only have one value. By convention, we talk about that variable's value, but we really mean its first (and only) value.
Other variables, like <code>$PATH</code>, really do have multiple values. During variable expansion, the variable expands to become multiple arguments:
 
 <pre class="fish cli-dark">
&gt; echo $PATH
/usr/bin /bin /usr/sbin /sbin /usr/local/bin
</pre>Lists cannot contain other lists: there is no recursion. A variable is a list of strings, full stop.
Get the length of a list with <code>count</code>:
 
 <pre class="fish cli-dark">
&gt; count $PATH
5
</pre>You can append (or prepend) to a list by setting the list to itself, with some additional arguments. Here we append /usr/local/bin to $PATH:
 
 <pre class="fish cli-dark">
&gt; set PATH $PATH /usr/local/bin
</pre>You can access individual elements with square brackets. Indexing starts at 1 from the beginning, and -1 from the end:
 
 <pre class="fish cli-dark">
&gt; echo $PATH
/usr/bin /bin /usr/sbin /sbin /usr/local/bin
&gt; echo $PATH[1]
/usr/bin
&gt; echo $PATH[-1]
/usr/local/bin
</pre>You can also access ranges of elements, known as "slices:"
 
 <pre class="fish cli-dark">
&gt; echo $PATH[1..2]
/usr/bin /bin
&gt; echo $PATH[-1..2]
/usr/local/bin /sbin /usr/sbin /bin
</pre>You can iterate over a list (or a slice) with a for loop:
 
 <pre class="fish cli-dark">
&gt; for val in $PATH
 echo "entry: $val"
 end
entry: /usr/bin/
entry: /bin
entry: /usr/sbin
entry: /sbin
entry: /usr/local/bin
</pre>Lists adjacent to other lists or strings are expanded as <a href="index.html#cartesian-product">cartesian products</a> unless quoted (see <a href="index.html#expand-variable">Variable expansion</a>):
 
 <pre class="fish cli-dark">
&gt; set -l a 1 2 3
&gt; set -l 1 a b c
&gt; echo $a$1
1a 2a 3a 1b 2b 3b 1c 2c 3c
&gt; echo $a" banana"
1 banana 2 banana 3 banana
&gt; echo "$a banana"
1 2 3 banana
</pre>This is similar to <a href="index.html#expand-brace">Brace expansion</a>.
<h1><a class="anchor" id="tut_command_substitutions"></a>
Command Substitutions</h1>
Command substitutions use the output of one command as an argument to another. Unlike other shells, <code>fish</code> does not use backticks ` for command substitutions. Instead, it uses parentheses:
 
 <pre class="fish cli-dark">
&gt; echo In (pwd), running (uname)
In /home/tutorial, running FreeBSD
</pre>A common idiom is to capture the output of a command in a variable:
 
 <pre class="fish cli-dark">
&gt; set os (uname)
&gt; echo $os
Linux
</pre>Command substitutions are not expanded within quotes. Instead, you can temporarily close the quotes, add the command substitution, and reopen them, all in the same argument:
 
 <pre class="fish cli-dark">
&gt; touch "testing_"(date +%s)".txt"
&gt; ls *.txt
testing_1360099791.txt
</pre><h1><a class="anchor" id="tut_combiners"></a>
Combiners (And, Or, Not)</h1>
Unlike other shells, <code>fish</code> does not have special syntax like &amp;&amp; or || to combine commands. Instead it has commands <code>and</code>, <code>or</code>, and <code>not</code>.
 
 <pre class="fish cli-dark">
&gt; cp file1.txt file1_bak.txt; and echo "Backup successful"; or echo "Backup failed"
Backup failed
</pre><h1><a class="anchor" id="tut_conditionals"></a>
Conditionals (If, Else, Switch)</h1>
Use <code>if</code>, <code>else if</code>, and <code>else</code> to conditionally execute code, based on the exit status of a command.
 
 <pre class="fish cli-dark">
if grep fish /etc/shells
 echo Found fish
else if grep bash /etc/shells
 echo Found bash
else
 echo Got nothing
end
</pre>There is also a <code>switch</code> command:
 
 <pre class="fish cli-dark">
switch (uname)
case Linux
 echo Hi Tux!
case Darwin
 echo Hi Hexley!
case FreeBSD NetBSD DragonFly
 echo Hi Beastie!
case '*'
 echo Hi, stranger!
end
</pre>Note that <code>case</code> does not fall through, and can accept multiple arguments or (quoted) wildcards.
<h1><a class="anchor" id="tut_functions"></a>
Functions</h1>
A <code>fish</code> function is a list of commands, which may optionally take arguments. Unlike other shells, arguments are not passed in "numbered variables" like <code>$1</code>, but instead in a single list <code>$argv</code>. To create a function, use the <code>function</code> builtin:
 
 <pre class="fish cli-dark">
&gt; function say_hello
 echo Hello $argv
 end
&gt; say_hello
Hello
&gt; say_hello everybody!
Hello everybody!
</pre>Unlike other shells, <code>fish</code> does not have aliases or special prompt syntax. Functions take their place.
You can list the names of all functions with the <code>functions</code> keyword (note the plural!). <code>fish</code> starts out with a number of functions:
 
 <pre class="fish cli-dark">
&gt; functions
alias, cd, delete-or-exit, dirh, dirs, down-or-search, eval, export, fish_command_not_found_setup, fish_config, fish_default_key_bindings, fish_prompt, fish_right_prompt, fish_sigtrap_handler, fish_update_completions, funced, funcsave, grep, help, history, isatty, ls, man, math, nextd, nextd-or-forward-word, open, popd, prevd, prevd-or-backward-word, prompt_pwd, psub, pushd, seq, setenv, trap, type, umask, up-or-search, vared
</pre>You can see the source for any function by passing its name to <code>functions</code>:
 
 <pre class="fish cli-dark">
&gt; functions ls
function ls --description 'List contents of directory'
 command ls -G $argv
end
</pre><h1><a class="anchor" id="tut_loops"></a>
Loops</h1>
While loops:
 
 <pre class="fish cli-dark">
&gt; while true
 echo "Loop forever"
end
Loop forever
Loop forever
Loop forever
...
</pre>For loops can be used to iterate over a list. For example, a list of files:
 
 <pre class="fish cli-dark">
&gt; for file in *.txt
 cp $file $file.bak
end
</pre>Iterating over a list of numbers can be done with <code>seq</code>:
 
 <pre class="fish cli-dark">
&gt; for x in (seq 5)
 touch file_$x.txt
end
</pre><h1><a class="anchor" id="tut_prompt"></a>
Prompt</h1>
Unlike other shells, there is no prompt variable like PS1. To display your prompt, <code>fish</code> executes a function with the name <code>fish_prompt</code>, and its output is used as the prompt.
You can define your own prompt:
 
 <pre class="fish cli-dark">
&gt; function fish_prompt
 echo "New Prompt % "
end
New Prompt % 
</pre>Multiple lines are OK. Colors can be set via <code>set_color</code>, passing it named ANSI colors, or hex RGB values:
 
 <pre class="fish cli-dark">
&gt; function fish_prompt
 set_color purple
 date "+%m/%d/%y"
 set_color FF0
 echo (pwd) '&gt;'
 set_color normal
 end
02/06/13
/home/tutorial &gt; 
</pre>You can choose among some sample prompts by running <code>fish_config prompt</code>. <code>fish</code> also supports RPROMPT through <code>fish_right_prompt</code>.
<h1><a class="anchor" id="tut_path"></a>
$PATH</h1>
<code>$PATH</code> is an environment variable containing the directories in which <code>fish</code> searches for commands. Unlike other shells, $PATH is a <a href="#tut_lists">list</a>, not a colon-delimited string.
To prepend /usr/local/bin and /usr/sbin to <code>$PATH</code>, you can write:
 
 <pre class="fish cli-dark">
&gt; set PATH /usr/local/bin /usr/sbin $PATH
</pre>You can do so directly in <code>config.fish</code>, like you might do in other shells with <code>.profile</code>. See <a href="#path_example">this example</a>.
A faster way is to modify the <code>$fish_user_paths</code> <a href="#tut_universal">universal variable</a>, which is automatically prepended to <code>$PATH</code>. For example, to permanently add <code>/usr/local/bin</code> to your <code>$PATH</code>, you could write:
 
 <pre class="fish cli-dark">
&gt; set -U fish_user_paths /usr/local/bin $fish_user_paths
</pre>The advantage is that you don't have to go mucking around in files: just run this once at the command line, and it will affect the current session and all future instances too. (Note: you should NOT add this line to <code>config.fish</code>. If you do, the variable will get longer each time you run fish!)
<h1><a class="anchor" id="tut_startup"></a>
Startup (Where's .bashrc?)</h1>
<code>fish</code> starts by executing commands in <code>~/.config/fish/config.fish</code>. You can create it if it does not exist.
It is possible to directly create functions and variables in <code>config.fish</code> file, using the commands shown above. For example:
<a class="anchor" id="path_example"></a> 
 <pre class="fish cli-dark">
&gt; cat ~/.config/fish/config.fish

set -x PATH $PATH /sbin/

function ll
 ls -lh $argv
end
</pre>However, it is more common and efficient to use autoloading functions and universal variables.
<h1><a class="anchor" id="tut_autoload"></a>
Autoloading Functions</h1>
When <code>fish</code> encounters a command, it attempts to autoload a function for that command, by looking for a file with the name of that command in <code>~/.config/fish/functions/</code>.
For example, if you wanted to have a function <code>ll</code>, you would add a text file <code>ll.fish</code> to <code>~/.config/fish/functions</code>:
 
 <pre class="fish cli-dark">
&gt; cat ~/.config/fish/functions/ll.fish
function ll
 ls -lh $argv
end
</pre>This is the preferred way to define your prompt as well:
 
 <pre class="fish cli-dark">
&gt; cat ~/.config/fish/functions/fish_prompt.fish
function fish_prompt
 echo (pwd) "&gt; "
end
</pre>See the documentation for <a href="commands.html#funced">funced</a> and <a href="commands.html#funcsave">funcsave</a> for ways to create these files automatically.
<h1><a class="anchor" id="tut_universal"></a>
Universal Variables</h1>
A universal variable is a variable whose value is shared across all instances of <code>fish</code>, now and in the future – even after a reboot. You can make a variable universal with <code>set -U</code>:
 
 <pre class="fish cli-dark">
&gt; set -U EDITOR vim
</pre>Now in another shell:
 
 <pre class="fish cli-dark">
&gt; echo $EDITOR
vim
</pre><h1><a class="anchor" id="tut_more"></a>
Ready for more?</h1>
If you want to learn more about fish, there is <a href="index.html">lots of detailed documentation</a>, an <a href="https://lists.sourceforge.net/lists/listinfo/fish-users">official mailing list</a>, the IRC channel #fish on <code>irc.oftc.net</code>, and the <a href="https://github.com/fish-shell/fish-shell/">github page</a>.

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