fish-shell/doc_src/cmds/echo.rst

.. _cmd-echo:

echo - display a line of text
=============================

Synopsis
--------

.. synopsis::

    echo [OPTIONS] [STRING]

Description
-----------

.. only:: builder_man

          NOTE: This page documents the fish builtin ``echo``.
          To see the documentation on any non-fish versions, use ``command man echo``.

``echo`` displays *STRING* of text.

The following options are available:

**-n**
    Do not output a newline.

**-s**
    Do not separate arguments with spaces.

**-E**
    Disable interpretation of backslash escapes (default).

**-e**
    Enable interpretation of backslash escapes.

Unlike other shells, this echo accepts ``--`` to signal the end of the options.

Escape Sequences
----------------

If ``-e`` is used, the following sequences are recognized:

- ``\`` backslash

- ``\a`` alert (BEL)

- ``\b`` backspace

- ``\c`` produce no further output

- ``\e`` escape

- ``\f`` form feed

- ``\n`` new line

- ``\r`` carriage return

- ``\t`` horizontal tab

- ``\v`` vertical tab

- ``\0NNN`` byte with octal value NNN (1 to 3 digits)

- ``\xHH`` byte with hexadecimal value HH (1 to 2 digits)

Example
-------

::

   > echo 'Hello World'
   Hello World

   > echo -e 'Top\nBottom'
   Top
   Bottom

   > echo -- -n
   -n

See Also
--------

- the :doc:`printf <printf>` command, for more control over output formatting
docs: Add labels to all commands This allows us to use :ref: references, which don't require hardcoding it as html [ci skip] 2019-03-31 17:05:09 +08:00			`.. _cmd-echo:`

Switch command docs from \section to reStructuredText 2018-12-17 09:39:33 +08:00			`echo - display a line of text`
Fix command section separator line lengths 2019-01-03 12:10:47 +08:00			`=============================`
Switch command docs from \section to reStructuredText 2018-12-17 09:39:33 +08:00
Migrate the 'synopsis' sections to .rst format 2018-12-18 09:58:24 +08:00			`Synopsis`
			`--------`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
docs synopsis: add HTML highlighing and automate manpage markup Recent synopsis changes move from literal code blocks to [RST line blocks]. This does not translate well to HTML: it's not rendered in monospace, so aligment is lost. Additionally, we don't get syntax highlighting in HTML, which adds differences to our code samples which are highlighted. We hard-wrap synopsis lines (like code blocks). To align continuation lines in manpages we need [backslashes in weird places]. Combined with the *, , and `` markup, it's a bit hard to get the alignment right. Fix these by moving synopsis sources back to code blocks and compute HTML syntax highlighting and manpage markup with a custom Sphinx extension. The new Pygments lexer can tokenize a synopsis and assign the various highlighting roles, which closely matches fish's syntax highlighing: - command/keyword (dark blue) - parameter (light blue) - operator like and/or/not/&&/\|\| (cyan) - grammar metacharacter (black) For manpage output, we don't project the fish syntax highlighting but follow the markup convention in GNU's man(1): bold text type exactly as shown. italic text replace with appropriate argument. To make it easy to separate these two automatically, formalize that (italic) placeholders must be uppercase; while all lowercase text is interpreted literally (so rendered bold). This makes manpages more consistent, see string-join(1) and and(1). Implementation notes: Since we want manpage formatting but Sphinx's Pygments highlighing plugin does not support manpage output, add our custom "synopsis" directive. This directive parses differently when manpage output is specified. This means that the HTML and manpage build processes must not share a cache, because the parsed doctrees are cached. Work around this by using separate cache locations for build targets "sphinx-docs" (which creates HTML) and "sphinx-manpages". A better solution would be to only override Sphinx's ManualPageBuilder but that would take a bit more code (ideally we could override ManualPageWriter but Sphinx 4.3.2 doesn't really support that). --- Alternative solution: stick with line blocks but use roles like :command: or :option: (or custom ones). While this would make it possible to produce HTML that is consistent with code blocks (by adding a bit of CSS), the source would look uglier and is harder to maintain. (Let's say we want to add custom formatting to the [\|] metacharacters in HTML. This is much easier with the proposed patch.) --- [RST line blocks]: https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#line-blocks [backslashes in weird places]: https://github.com/fish-shell/fish-shell/pull/8626#discussion_r782837750 2022-01-09 22:09:46 +08:00			`.. synopsis::`

docs synopsis: make all placeholder arguments uppercase man(1) uses lowercase placeholders but we usually don't. Additionally, the new synopsis autoformatting only recognizes placeholders if they are uppercase. Use uppercase for all placeholders. 2022-01-17 12:29:49 +08:00			`echo [OPTIONS] [STRING]`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Convert \\subsection sections into rst format 2018-12-19 10:44:30 +08:00			`Description`
Fix command section separator line lengths 2019-01-03 12:10:47 +08:00			`-----------`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Reference more non-fish shell builtins that have relevant differences When writing scripts for other shells, it can be confusing and annoying that our `man` function shadows other manual pages, for example `exec(1p)` from [Linux man-pages]. I almost never want to see the fish variant for such contended cases (which obviuosly don't include fish-specific commands like `string`, only widely-known shell builtins). For the contented cases like `exec`, the POSIX documentation is more substantial and useful, since it describes a (sub)set of languages widely used for scripting. Because of this I think we should stop overriding the system's man pages. Nowadays we offer `exec -h` as intuitive way to show the documentation for the fish-specific command (note that `help` is not a good replacement because it uses a web browser). Looking through the contended commands, it seems like for most of them, the fish version is not substantially different from the system version. A notable exception is `read` but I don't think it's a very important one. So I think we should can sacrifice a bit of the native fish-scripting experience in exchange for playing nicer with other shells. I think the latter is more important because scripting is not our focus, the way I see it. So maybe put our manpath at the end. In lieu of that, let's at least have `exec.rst` reference the system variant. [Linux man-pages]: https://www.kernel.org/doc/man-pages/ Closes #10376 2024-03-16 23:45:00 +08:00			`.. only:: builder_man`

			NOTE: This page documents the fish builtin ``echo``.
			To see the documentation on any non-fish versions, use ``command man echo``.

Commit doc_src progress. This is continuing the work I've been doing to remove the :: formatting for the synopsis sections of our manual pages. 2021-12-18 05:58:38 +08:00			``echo`` displays STRING of text.
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
			`The following options are available:`

docs: removed enumeration item from echo docs 2022-04-23 00:43:50 +08:00			`-n`
docs: standardise on definition lists for options Harmonizes the option listing including formatting in a similar manner to the synopsis of each entry. 2022-03-11 23:56:20 +08:00			`Do not output a newline.`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
docs: standardise on definition lists for options Harmonizes the option listing including formatting in a similar manner to the synopsis of each entry. 2022-03-11 23:56:20 +08:00			`-s`
			`Do not separate arguments with spaces.`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
docs: standardise on definition lists for options Harmonizes the option listing including formatting in a similar manner to the synopsis of each entry. 2022-03-11 23:56:20 +08:00			`-E`
			`Disable interpretation of backslash escapes (default).`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
docs: standardise on definition lists for options Harmonizes the option listing including formatting in a similar manner to the synopsis of each entry. 2022-03-11 23:56:20 +08:00			`-e`
			`Enable interpretation of backslash escapes.`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Document that echo takes `--` [ci skip] 2020-08-20 01:00:20 +08:00			Unlike other shells, this echo accepts ``--`` to signal the end of the options.

Convert \\subsection sections into rst format 2018-12-19 10:44:30 +08:00			`Escape Sequences`
Fix command section separator line lengths 2019-01-03 12:10:47 +08:00			`----------------`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			If ``-e`` is used, the following sequences are recognized:
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\`` backslash
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\a`` alert (BEL)
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\b`` backspace
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\c`` produce no further output
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\e`` escape
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\f`` form feed
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\n`` new line
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\r`` carriage return
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\t`` horizontal tab
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\v`` vertical tab
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\0NNN`` byte with octal value NNN (1 to 3 digits)
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch backticks to double backticks for rst compatibility 2018-12-20 04:02:45 +08:00			- ``\xHH`` byte with hexadecimal value HH (1 to 2 digits)
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Convert \\subsection sections into rst format 2018-12-19 10:44:30 +08:00			`Example`
Fix command section separator line lengths 2019-01-03 12:10:47 +08:00			`-------`
Copy doc_src to sphinx_doc_src and add a TOC 2018-12-17 05:08:41 +08:00
Switch \fish sections to rst format 2018-12-19 11:14:04 +08:00			`::`

Document that echo takes `--` [ci skip] 2020-08-20 01:00:20 +08:00			`> echo 'Hello World'`
			`Hello World`
Switch \fish sections to rst format 2018-12-19 11:14:04 +08:00
docs: Use \ instead of \\ in examples (#7286) Instead of informing the bell character (hex 07), the example was using an escaped \ followed by x07. $ echo \\x07 \x07 $ echo \x07 $ echo \x07 \| od -a 0000000 bel nl 0000002 $ * docs: Use \u instead of \\u Instead of informing the Unicode character 慡, this example was using an escaped \ followed by u6161. $ echo \\u6161 \u6161 $ echo \u6161 慡 Before: $ string escape --style=var 'a1 b2'\\u6161 \| string unescape --style=var a1 b2\u6161 Now: $ string escape --style=var 'a1 b2'\u6161 \| string unescape --style=var a1 b2慡 2020-08-27 00:29:03 +08:00			`> echo -e 'Top\nBottom'`
Document that echo takes `--` [ci skip] 2020-08-20 01:00:20 +08:00			`Top`
			`Bottom`
Switch \fish sections to rst format 2018-12-19 11:14:04 +08:00
Document that echo takes `--` [ci skip] 2020-08-20 01:00:20 +08:00			`> echo -- -n`
			`-n`
doc: add interlinks between `echo` ←→ `printf` commands 2020-03-01 20:43:14 +08:00
			`See Also`
			`--------`

docs: Use :doc: role when linking to commands This makes it so we link to the very top of the document instead of a special anchor we manually include. So clicking e.g. :doc:`string <cmds/string>` will link you to cmds/string.html instead of cmds/string.html#cmd-string. I would love to have a way to say "this document from the root of the document path", but that doesn't appear to work, I tried `/cmds/string`. So we'll just have to use cmds/string in normal documents and plain `string` from other commands. 2022-09-24 01:57:49 +08:00			- the :doc:`printf <printf>` command, for more control over output formatting