nano/doc/nano.texi

\input texinfo  @c -*-texinfo-*-
@c %**start of header
@setfilename nano.info
@settitle nano
@c %**end of header

@documentencoding UTF-8

@smallbook
@set EDITION 0.5
@set VERSION 2.9.4
@set UPDATED March 2018

@dircategory Editors
@direntry
* nano: (nano).                 Small and friendly text editor.
@end direntry

@c tex
@c \overfullrule=0pt
@c end tex

@titlepage
@title GNU @command{nano}
@subtitle a small and friendly text editor
@subtitle version 2.9.4

@author Chris Allegretta
@page

This manual documents the GNU @command{nano} editor.
@sp 1
This manual is part of the GNU @command{nano} distribution.@*

@sp 4
Copyright @copyright{} 1999-2009, 2014-2017 Free Software Foundation, Inc.

@sp 1
This document is dual-licensed.  You may distribute and/or modify it
under the terms of either of the following licenses:

@sp 1
* The GNU General Public License, as published by the Free Software
  Foundation, version 3 or (at your option) any later version.  You
  should have received a copy of the GNU General Public License along
  with this program.  If not, see @url{http://www.gnu.org/licenses/}.

@sp 1
* The GNU Free Documentation License, as published by the Free Software
  Foundation, version 1.2 or (at your option) any later version, with no
  Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
  You should have received a copy of the GNU Free Documentation License
  along with this program.  If not, see @url{http://www.gnu.org/licenses/}.

@sp 1
You may contact the author by
e-mail: @email{chrisa@@asty.org}@*
@end titlepage


@ifnottex

@node Top
@top

This manual documents the GNU @command{nano} editor, version 2.9.4.

@menu
* Introduction::
* Invoking::
* Command-line Options::
* Editor Basics::
* Built-in Help::
* Feature Toggles::
* Nanorc Files::
* The File Browser::
* Pico Compatibility::
* Building and Configure Options::
@end menu

@end ifnottex


@node Introduction
@chapter Introduction

GNU @command{nano} is a small and friendly text editor.  Besides basic text
editing, @command{nano} offers many extra features, such as an interactive
search-and-replace, undo/redo, syntax coloring, smooth scrolling,
auto-indentation, go-to-line-and-column-number, feature toggles,
file locking, backup files, and internationalization support.

The original goal for @command{nano} was to be a complete bug-for-bug
emulation of Pico.  But currently the goal is to be as compatible
as possible while offering a superset of Pico's functionality.
@xref{Pico Compatibility} for more details on how @command{nano} and
Pico differ.

Please report bugs via @url{https://savannah.gnu.org/bugs/?group=nano}.


@node Invoking
@chapter Invoking

The usual way to invoke @command{nano} is:

@iftex
@sp 1
@end iftex
@example
@code{nano [FILE]}
@end example
@iftex
@sp 1
@end iftex

But it is also possible to specify one or more options (see the next
section), and to edit several files in a row.  Additionally, the cursor
can be put on a specific line of a file by adding the line number
with a plus sign before the filename, and even in a specific column by
adding it with a comma.  So a more complete command synopsis is:

@iftex
@sp 1
@end iftex
@example
@code{nano [OPTION]@dots{} [[+LINE[,COLUMN]|+,COLUMN] FILE]@dots{}}
@end example
@iftex
@sp 1
@end iftex

Normally, however, you set your preferred options in a @file{nanorc}
file (@pxref{Nanorc Files}).  And when using @code{set positionlog}
(making @command{nano} remember the cursor position when you close a file),
you will rarely need to specify a line number.

As a special case: when instead of a filename a dash is given, @command{nano}
will read data from standard input.  This means you can pipe the output of
a command straight into a buffer, and then edit it.

@node Command-line Options
@chapter Command-line Options

@command{nano} takes the following options from the command line:

@table @option

@item -A
@itemx --smarthome
Make the Home key smarter.  When Home is pressed anywhere but at the
very beginning of non-whitespace characters on a line, the cursor will
jump to that beginning (either forwards or backwards).  If the cursor is
already at that position, it will jump to the true beginning of the
line.

@item -B
@itemx --backup
When saving a file, back up the previous version of it, using the current
filename suffixed with a tilde (@code{~}).

@item -C @var{directory}
@itemx --backupdir=@var{directory}
Make and keep not just one backup file, but make and keep a uniquely
numbered one every time a file is saved --- when backups are enabled.
The uniquely numbered files are stored in the specified directory.

@item -D
@itemx --boldtext
Use bold text instead of reverse video text.

@item -E
@itemx --tabstospaces
Convert typed tabs to spaces.

@item -F
@itemx --multibuffer
Read a file into a new buffer by default.

@item -G
@itemx --locking
Enable vim-style file locking when editing files.

@item -H
@itemx --historylog
Save the last hundred search strings and replacement strings and
executed commands, so they can be easily reused in later sessions.

@item -I
@itemx --ignorercfiles
Don't look at the system's nanorc file nor at the user's nanorc.

@item -K
@itemx --rebindkeypad
Interpret the numeric keypad keys so that they all work properly.  You
should only need to use this option if they don't, as mouse support
won't work properly with this option enabled.

@item -L
@itemx --nonewlines
Don't add newlines to the ends of files.

@item -M
@itemx --trimblanks
Snip trailing whitespace from the wrapped line when automatic
hard-wrapping occurs or when text is justified.

@item -N
@itemx --noconvert
Disable automatic conversion of files from DOS/Mac format.

@item -O
@itemx --morespace
Use the blank line below the title bar as extra editing space.

@item -P
@itemx --positionlog
For the 200 most recent files, log the last position of the cursor,
and place it at that position again upon reopening such a file.

@item -Q "@var{characters}"
@itemx --quotestr="@var{characters}"
Set the quoting string for justifying.  The default value is
@t{"^([ \t]*[|>:@}#])+"} if extended regular expression support
is available, and @t{"> "} otherwise.
Note that @code{\t} stands for a literal Tab character.

@item -R
@itemx --restricted
Restricted mode: don't read or write to any file not specified on the
command line; don't read any nanorc files nor history files; don't allow
suspending nor spell checking; don't
allow a file to be appended to, prepended to, or saved under a different
name if it already has one; and don't use backup files.
This restricted mode is also accessible by invoking @command{nano} with
any name beginning with @code{r} (e.g.@: @command{rnano}).

@item -S
@itemx --smooth
Enable smooth scrolling.  Text will scroll line-by-line, instead of the
usual chunk-by-chunk behavior.

@item -T @var{number}
@itemx --tabsize=@var{number}
Set the displayed tab length to @var{number} columns.  The value of
@var{number} must be greater than 0.  The default value is @t{8}.

@item -U
@itemx --quickblank
Do quick status-bar blanking: status-bar messages will disappear after 1
keystroke instead of 25.  Note that option @option{-c}
(@option{--constantshow}) overrides this.

@item -V
@itemx --version
Show the current version number and exit.

@item -W
@itemx --wordbounds
Detect word boundaries differently by treating punctuation
characters as parts of words.

@item -X "@var{characters}"
@itemx --wordchars="@var{characters}"
Specify which other characters (besides the normal alphanumeric ones)
should be considered as parts of words.  This overrides option
@option{-W} (@option{--wordbounds}).

@item -Y @var{name}
@itemx --syntax=@var{name}
Specify the syntax to be used for highlighting.
@xref{Syntax Highlighting} for more info.

@item -a
@itemx --atblanks
When doing soft line wrapping, wrap lines at whitespace
instead of always at the edge of the screen.

@item -c
@itemx --constantshow
Constantly display the cursor position (line number, column number,
and character number) on the status bar.
Note that this overrides option @option{-U} (@option{--quickblank}).

@item -d
@itemx --rebinddelete
Interpret the Delete key differently so that both Backspace and Delete
work properly.  You should only need to use this option if Backspace
acts like Delete on your system.

@item -g
@itemx --showcursor
Make the cursor visible in the file browser, putting it on the
highlighted item.  Useful for braille users.

@item -h
@itemx --help
Show a summary of command-line options and exit.

@item -i
@itemx --autoindent
Automatically indent new lines to the same number of spaces and tabs as
the previous line.

@item -k
@itemx --cutfromcursor
Make the 'Cut Text' command (normally @kbd{^K}) cut from the current cursor
position to the end of the line, instead of cutting the entire line.

@item -l
@itemx --linenumbers
Display line numbers to the left of the text area.

@item -m
@itemx --mouse
Enable mouse support, if available for your system.  When enabled, mouse
clicks can be used to place the cursor, set the mark (with a double
click), and execute shortcuts.  The mouse will work in the X Window
System, and on the console when gpm is running.  Text can still be
selected through dragging by holding down the Shift key.

@item -n
@itemx --noread
Treat any name given on the command line as a new file.  This allows
@command{nano} to write to named pipes: it will start with a blank buffer,
and will write to the pipe when the user saves the "file".  This way
@command{nano} can be used as an editor in combination with for instance
@command{gpg} without having to write sensitive data to disk first.

@item -o @var{directory}
@itemx --operatingdir=@var{directory}
Set the operating directory.  This makes @command{nano} set up something
similar to a chroot.

@item -p
@itemx --preserve
Preserve the @kbd{^Q} (XON) and @kbd{^S} (XOFF) sequences so data being
sent to the editor can be stopped and started.

@item -q
@itemx --quiet
Obsolete option.  Recognized but ignored.

@item -r @var{number}
@itemx --fill=@var{number}
Hard-wrap lines at column @var{number} (by inserting a newline character).
If the given value is 0 or less, wrapping will occur at the width of
the screen minus the given amount, allowing the wrapping width to
vary along with the width of the screen if and when it is resized.
The default value is @t{-8}.  This option conflicts with @option{-w}
(@option{--nowrap}); the last one given takes effect.

@anchor{@option{--speller}}
@item -s @var{program}
@itemx --speller=@var{program}
Use the given program to do spell checking and correcting.  By default,
@command{nano} uses the command specified in the @env{SPELL} environment
variable for this.  If @env{SPELL} is not set, and @option{--speller} is
not specified either, then @command{nano} uses its own interactive spell
corrector, which requires the GNU @command{spell} program to be installed.

@item -t
@itemx --tempfile
Don't ask whether to save a modified buffer when exiting with @kbd{^X}, but
assume yes.  This option is useful when @command{nano} is used as the
composer of a mailer program.

@item -u
@item --unix
Save a file by default in Unix format.  This overrides nano's
default behavior of saving a file in the format that it had.
(This option has no effect when you also use @option{--noconvert}.)

@item -v
@itemx --view
Don't allow the contents of the file to be altered.  Note that this
option should NOT be used in place of correct file permissions to
implement a read-only file.

@item -w
@itemx --nowrap
Don't hard-wrap long lines at any length.  This option conflicts with
@option{-r} (@option{--fill}); the last one given takes effect.

@anchor{Expert Mode}
@item -x
@itemx --nohelp
Expert Mode: don't show the Shortcut List at the bottom of the screen.
This affects the location of the status bar as well, as in Expert Mode it
is located at the very bottom of the editor.

Note: When accessing the help system, Expert Mode is temporarily
disabled to display the help-system navigation keys.

@item -z
@itemx --suspend
Enable the ability to suspend @command{nano} using the system's suspend
keystroke (usually @kbd{^Z}).

@item -$
@itemx --softwrap
Enable 'soft wrapping'.  This will make @command{nano} attempt to display the
entire contents of any line, even if it is longer than the screen width, by
continuing it over multiple screen lines.  Since
@code{$} normally refers to a variable in the Unix shell, you should specify
this option last when using other options (e.g.@: @code{nano -wS$}) or pass it
separately (e.g.@: @code{nano -wS -$}).

@item -b
@itemx -e
@itemx -f
@itemx -j
Ignored, for compatibility with Pico.

@end table


@node Editor Basics
@chapter Editor Basics

@menu
* Entering Text::
* Commands::
* The Cutbuffer::
* The Mark::
* Screen Layout::
* Search and Replace::
* Using the Mouse::
* Limitations::
@end menu

@node Entering Text
@section Entering Text

@command{nano} is a "modeless" editor.  This means that all keystrokes,
with the exception of Control and Meta sequences, enter text into the
file being edited.

Characters not present on the keyboard can be entered in two ways:

@itemize @bullet
@item
For characters with a single-byte code,
pressing the Esc key twice and then typing a three-digit decimal number
(from @kbd{000} to @kbd{255}) will make @command{nano} behave as if you
typed the key with that value.

@item
For any possible character, pressing @kbd{M-V} (Alt+V) and then typing a
six-digit hexadecimal number (starting with @kbd{0} or @kbd{1}) will enter the
corresponding Unicode character into the buffer.
@end itemize

For example, typing @kbd{Esc Esc 2 3 4} will enter the character "ê" ---
useful when writing about a French party.  Typing @kbd{M-V 0 0 2 2 c 4}
will enter the symbol "⋄", a little diamond.

@node Commands
@section Commands

Commands are given by using the Control key (Ctrl, shown as @kbd{^})
or the Meta key (Alt or Cmd, shown as @kbd{M-}).

@itemize @bullet
@item
A control-key sequence is entered by holding down the Ctrl key and
pressing the desired key.

@item
A meta-key sequence is entered by holding down the Meta key (normally
the Alt key) and pressing the desired key.
@end itemize

If for some reason on your system the combinations with Ctrl or Alt do
not work, you can generate them by using the Esc key.  A control-key
sequence is generated by pressing the Esc key twice and then pressing
the desired key, and a meta-key sequence by pressing the Esc key once
and then pressing the desired key.

@node The Cutbuffer
@section The Cutbuffer

Text can be cut from a file, a whole line at a time, by using the 'Cut Text'
command (default key binding: @kbd{^K}).  The cut line is stored in
the cutbuffer.  Consecutive strokes of @kbd{^K} will add each cut line
to this buffer, but a @kbd{^K}
after any other keystroke will overwrite the entire cutbuffer.

The contents of the cutbuffer can be pasted back into the file with the
'Uncut Text' command (default key binding: @kbd{^U}).

A line of text can be copied into the cutbuffer (without cutting it) with
the 'Copy Text' command (default key binding: @kbd{M-6}).

@node The Mark
@section The Mark

Text can be selected by first 'setting the Mark' (default key bindings:
@kbd{^6} and @kbd{M-A}) and then moving the cursor to the other end of the portion
to be selected.  The selected portion of text will be highlighted.
This selection can now be cut or copied in its entirety with a single
@kbd{^K} or @kbd{M-6}.  Or the selection can be used to limit the scope of
a search-and-replace (@kbd{^\}) or spell-checking session (@kbd{^T}).

On some terminals, it is also possible to select text by holding down
@kbd{Shift} together with the cursor keys.  Such a selection is cancelled
upon any cursor movement where @kbd{Shift} isn't held.

Cutting or copying selected text will toggle the mark off automatically.
If necessary, it can be toggled off manually with another @kbd{^6} or @kbd{M-A}.

@node Screen Layout
@section Screen Layout

The default screen of nano consists of five areas.  From top to bottom
these are: the title bar, a blank line, the edit window, the status bar,
and two help lines.

The title bar consists of
three sections: left, center and right.  The section on the left
displays the version of @command{nano} being used.  The center section
displays the current filename, or "New Buffer" if the file has not yet
been named.  The section on the right displays "Modified" if the
file has been modified since it was last saved or opened.

The status bar is the third line from the bottom of the screen.  It
shows important and informational messages.  Any error messages that
occur from using the editor will appear on the status bar.  Any questions
that are asked of the user will be asked on the status bar, and any user
input (search strings, filenames, etc.) will be input on the status bar.

The two help lines at the bottom of the screen show some of the most
essential functions of the editor.  These two lines are called the
Shortcut List.

@node Search and Replace
@section Search and Replace

One can search the current buffer for the occurrence of any string
with the Search command (default key binding: @kbd{^W}).  The default search
mode is forward, case-insensitive, and for literal strings.  But one
can search backwards by pressing @kbd{M-B}, search case sensitively with @kbd{M-C},
and interpret regular expressions in the search string with @kbd{M-R}.

A regular expression in a search string always covers just one line;
it cannot span multiple lines.  And when replacing (with @kbd{^\} or @kbd{M-R})
the replacement string cannot contain a newline (LF).

@node Using the Mouse
@section Using the Mouse

When mouse support has been configured and enabled, a single mouse click
places the cursor at the indicated position.  Clicking a second time in
the same position toggles the mark.  Clicking in the shortcut list
executes the selected shortcut.  To be able to select text with the
left button, or paste text with the middle button, hold down the
Shift key during those actions.

The mouse will work in the X Window System, and on the console when gpm
is running.

@node Limitations
@section Limitations

Justifications (@kbd{^J})
are not yet covered by the general undo system.  So after a justification
that is not immediately undone, earlier edits
cannot be undone any more.  The workaround is, of course, to exit without
saving.

The recording and playback of keyboard macros works correctly only on a
terminal emulator, not on a Linux console (VT), because the latter is a
deficient terminal.

@node Built-in Help
@chapter Built-in Help

The built-in help system in @command{nano} is available by pressing @kbd{^G}.
It is fairly self-explanatory.  It documents the various parts of the
editor and the available keystrokes.  Navigation is via the @kbd{^Y} (Page Up)
and @kbd{^V} (Page Down) keys.  @kbd{^X} exits from the help system.


@node Feature Toggles
@chapter Feature Toggles

Toggles allow you to change on-the-fly certain aspects of the editor
which would normally be specified via command-line options.  They are
invoked via Meta-key sequences (@pxref{Commands} for more info).
The following global toggles are available:

@table @code

@item Backup Files toggle
@kbd{Meta-B} toggles the @option{-B} (@option{--backup}) command-line option.

@item Constant Cursor Position Display toggle
@kbd{Meta-C} toggles the @option{-c} (@option{--constantshow}) command-line option.

@item Multiple File Buffers toggle
@kbd{Meta-F} toggles the @option{-F} (@option{--multibuffer}) command-line option.

@item Smart Home Key toggle
@kbd{Meta-H} toggles the @option{-A} (@option{--smarthome}) command-line option.

@item Auto Indent toggle
@kbd{Meta-I} toggles the @option{-i} (@option{--autoindent}) command-line option.

@item Cut From Cursor To End-of-Line toggle
@kbd{Meta-K} toggles the @option{-k} (@option{--cutfromcursor}) command-line option.

@item Long-Line Wrapping toggle
@kbd{Meta-L} toggles the @option{-w} (@option{--nowrap}) command-line option.

@item Mouse Support toggle
@kbd{Meta-M} toggles the @option{-m} (@option{--mouse}) command-line option.

@item No Conversion From DOS/Mac Format toggle
@kbd{Meta-N} toggles the @option{-N} (@option{--noconvert}) command-line option.

@item More Space For Editing toggle
@kbd{Meta-O} toggles the @option{-O} (@option{--morespace}) command-line option.

@item Whitespace Display toggle
@kbd{Meta-P} toggles the whitespace-display mode (@pxref{Whitespace}).

@item Tabs To Spaces toggle
@kbd{Meta-Q} toggles the @option{-E} (@option{--tabstospaces}) command-line option.

@item Smooth Scrolling toggle
@kbd{Meta-S} toggles the @option{-S} (@option{--smooth}) command-line option.

@item Expert/No Help toggle
@kbd{Meta-X} toggles the @option{-x} (@option{--nohelp}) command-line option.

@item Color Syntax Highlighting toggle
@kbd{Meta-Y} toggles color syntax highlighting (if your nanorc defines syntaxes
--- @pxref{Syntax Highlighting}).

@item Suspension toggle
@kbd{Meta-Z} toggles the @option{-z} (@option{--suspend}) command-line option.

@item Line Numbers toggle
@kbd{Meta-#} toggles the @option{-l} (@option{--linenumbers}) command-line option.

@item Soft Wrapping toggle
@kbd{Meta-$} toggles the @option{-$} (@option{--softwrap}) command-line option.

@end table


@node Nanorc Files
@chapter Nanorc Files

The nanorc files contain the default settings for @command{nano}.  They
should be in Unix format, not in DOS or Mac format.  During startup,
@command{nano} will first read the system-wide settings, from /etc/nanorc
(the exact path might be different), and then the user-specific settings,
either from @file{~/.nanorc} or from @file{$XDG_CONFIG_HOME/nano/nanorc}
or from @file{.config/nano/nanorc}, whichever exists first.

A nanorc file accepts a series of "set" and "unset" commands, which can
be used to configure @command{nano} on startup without using command-line
options.  Additionally, there are some commands to define syntax highlighting
and to rebind keys --- @pxref{Syntax Highlighting} and @ref{Rebinding Keys}.
@command{nano} will read one command per line.

Options in nanorc files take precedence over @command{nano}'s defaults, and
command-line options override nanorc settings.  Also, options that do not
take an argument are unset by default.  So using the @code{unset} command
is only needed when wanting to override a setting of the system's nanorc
file in your own nanorc.  Options that take an argument cannot be unset.

Quotes inside string parameters don't have to be escaped with
backslashes.  The last double quote in the string will be treated as its
end.  For example, for the @code{brackets} option, @t{""')>]@}"} will match
@code{"}, @code{'}, @code{)}, @code{>}, @code{]}, and @code{@}}.

@menu
* Settings::
* Syntax Highlighting::
* Rebinding Keys::
@end menu

@node Settings
@section Settings

The supported settings in a nanorc file are:

@table @code

@item set allow_insecure_backup
When backing up files, allow the backup to succeed even if its
permissions can't be (re)set due to special OS considerations.
You should NOT enable this option unless you are sure you need it.

@item set atblanks
When soft line wrapping is enabled, make it wrap lines at blank characters
(tabs and spaces) instead of always at the edge of the screen.

@item set autoindent
Use auto-indentation.

@item set backup
When saving a file, back up the previous version of it, using the current
filename suffixed with a tilde (@code{~}).

@item set backupdir "@var{directory}"
Make and keep not just one backup file, but make and keep a uniquely
numbered one every time a file is saved --- when backups are enabled
with @code{set backup} or @option{--backup} or @option{-B}.
The uniquely numbered files are stored in the specified directory.

@item set backwards
Obsolete option.  Recognized but ignored.  @code{^Q} is available to
start a backward search.

@item set boldtext
Use bold instead of reverse video for the title bar, status bar, key combos,
function tags, line numbers, and selected text.  This can be overridden by
setting the options @code{titlecolor}, @code{statuscolor}, @code{keycolor},
@code{functioncolor}, @code{numbercolor}, and @code{selectedcolor}.

@item set brackets "@var{string}"
Set the characters treated as closing brackets when justifying
paragraphs.  This may not include blank characters.  Only closing
punctuation (see @code{set punct}), optionally followed by the specified
closing brackets, can end sentences.  The default value is
@t{"')>]@}"}.

@item set casesensitive
Do case-sensitive searches by default.

@item set constantshow
Constantly display the cursor position on the status bar.
Note that this overrides @option{quickblank}.

@item set cutfromcursor
Use cut-from-cursor-to-end-of-line by default, instead of cutting the whole line.
(The old form of this option, @code{set cut}, is deprecated.)

@item set errorcolor @var{fgcolor},@var{bgcolor}
Use this color combination for the status bar when an error message is displayed.
@xref{@code{set functioncolor}} for valid color names.

@item set fill @var{number}
Hard-wrap lines at column number @var{number}.  If @var{number} is 0 or less,
the maximum line length will be the screen width less @var{number} columns.
The default value is @t{-8}.  This option conflicts with
@option{nowrap}; the last one given takes effect.

@anchor{@code{set functioncolor}}
@item set functioncolor @var{fgcolor},@var{bgcolor}
Use this color combination for the concise function descriptions
in the two help lines at the bottom of the screen.
Valid names for foreground and background color are:
@code{white}, @code{black}, @code{blue}, @code{green},
@code{red}, @code{cyan}, @code{yellow}, @code{magenta}, and @code{normal}
--- where @code{normal} means the default foreground or background color.
The name of the foreground color may be prefixed with @code{bright}.
And either @var{fgcolor} or ,@var{bgcolor} may be left out.

@item set historylog
Save the last hundred search strings and replacement strings and
executed commands, so they can be easily reused in later sessions.

@item set keycolor @var{fgcolor},@var{bgcolor}
Use this color combination for the shortcut key combos
in the two help lines at the bottom of the screen.
@xref{@code{set functioncolor}} for valid color names.

@item set linenumbers
Display line numbers to the left of the text area.

@item set locking
Enable vim-style lock-files for when editing files.

@item set matchbrackets "@var{string}"
Set the opening and closing brackets that can be found by bracket
searches.  This may not include blank characters.  The opening set must
come before the closing set, and the two sets must be in the same order.
The default value is @t{"(<[@{)>]@}"}.

@item set morespace
Use the blank line below the title bar as extra editing space.

@item set mouse
Enable mouse support, so that mouse clicks can be used to place the
cursor, set the mark (with a double click), or execute shortcuts.

@item set multibuffer
When reading in a file with @kbd{^R}, insert it into a new buffer by default.

@item set noconvert
Don't convert files from DOS/Mac format.

@item set nohelp
Don't display the help lists at the bottom of the screen.

@item set nopauses
Don't pause between warnings at startup.  This means that only
the last one will be visible (when there are multiple ones).

@item set nonewlines
Don't add newlines to the ends of files.

@item set nowrap
Don't hard-wrap text at all.  This option conflicts with
@option{fill}; the last one given takes effect.

@item set numbercolor @var{fgcolor},@var{bgcolor}
Use this color combination for line numbers.
@xref{@code{set functioncolor}} for valid color names.

@item set operatingdir "@var{directory}"
@command{nano} will only read and write files inside "directory" and its
subdirectories.  Also, the current directory is changed to here, so
files are inserted from this directory.  By default, the operating
directory feature is turned off.

@item set positionlog
Save the cursor position of files between editing sessions.
The cursor position is remembered for the 200 most-recently edited files.

@item set preserve
Preserve the XON and XOFF keys (@kbd{^Q} and @kbd{^S}).

@item set punct "@var{string}"
Set the characters treated as closing punctuation when justifying
paragraphs.  This may not include blank characters.  Only the
specified closing punctuation, optionally followed by closing brackets
(see @code{set brackets}), can end sentences.
The default value is @t{"!.?"}.

@item set quickblank
Do quick status-bar blanking: status-bar messages will disappear after 1
keystroke instead of 25.  Note that @option{constantshow} overrides this.

@item set quiet
Obsolete option.  Recognized but ignored.

@item set quotestr "@var{string}"
The email-quote string, used to justify email-quoted paragraphs.  This
is an extended regular expression if your system supports them,
otherwise a literal string.  The default value is
@t{"^([ \\t]*[#:>\\|@}])+"} if you have extended regular expression
support, and @t{"> "} otherwise.
Note that @code{\t} stands for a literal Tab character.

@item set rebinddelete
Interpret the Delete key differently so that both Backspace and Delete
work properly.  You should only need to use this option if Backspace
acts like Delete on your system.

@item set rebindkeypad
Interpret the numeric keypad keys so that they all work properly.  You
should only need to use this option if they don't, as mouse support
won't work properly with this option enabled.

@item set regexp
Do extended regular expression searches by default.

@item set selectedcolor @var{fgcolor},@var{bgcolor}
Use this color combination for selected text.
@xref{@code{set functioncolor}} for valid color names.

@item set showcursor
Put the cursor on the highlighted item in the file browser, to aid
braille users.

@item set smarthome
Make the Home key smarter.  When Home is pressed anywhere but at the
very beginning of non-whitespace characters on a line, the cursor will
jump to that beginning (either forwards or backwards).  If the cursor is
already at that position, it will jump to the true beginning of the
line.

@item set smooth
Use smooth scrolling by default.

@item set softwrap
Enable soft line wrapping for easier viewing of very long lines.

@item set speller "@var{program}"
Use the given program to do spell checking and correcting.
@xref{@option{--speller}} for details.

@item set statuscolor @var{fgcolor},@var{bgcolor}
Use this color combination for the status bar.
@xref{@code{set functioncolor}} for valid color names.

@item set suspend
Allow @command{nano} to be suspended.

@item set tabsize @var{number}
Use a tab size of @var{number} columns.  The value of @var{number} must be
greater than 0.  The default value is @t{8}.

@item set tabstospaces
Convert typed tabs to spaces.

@item set tempfile
Save automatically on exit, don't prompt.

@item set titlecolor @var{fgcolor},@var{bgcolor}
Use this color combination for the title bar.
@xref{@code{set functioncolor}} for valid color names.

@item set trimblanks
Remove trailing whitespace from wrapped lines when automatic
hard-wrapping occurs or when text is justified.

@item set unix
Save a file by default in Unix format.  This overrides nano's
default behavior of saving a file in the format that it had.
(This option has no effect when you also use @code{set noconvert}.)

@item set view
Disallow file modification.

@anchor{Whitespace}
@item set whitespace "@var{string}"
Set the two characters used to indicate the presence of tabs and
spaces.  They must be single-column characters.  The default pair
for a UTF-8 locale is @t{"»·"}, and for other locales @t{">."}.

@item set wordbounds
Detect word boundaries differently by treating punctuation
characters as part of a word.

@item set wordchars "@var{string}"
Specify which other characters (besides the normal alphanumeric ones)
should be considered as parts of words.  This overrides the option
@code{wordbounds}.

@end table

@node Syntax Highlighting
@section Syntax Highlighting

Coloring the different syntactic elements of a file
is done via regular expressions (see the @code{color} command below).
This is inherently imperfect, because regular expressions are not
powerful enough to fully parse a file.  Nevertheless, regular
expressions can do a lot and are easy to make, so they are a
good fit for a small editor like @command{nano}.

A separate syntax can be defined for each kind of file
via the following commands in a nanorc file:

@table @code

@item syntax "@var{name}" ["@var{fileregex}" @dots{}]
Start the definition of a syntax with this @var{name}.
All subsequent @code{color} and other such commands
will be added to this syntax, until a new @code{syntax}
command is encountered.

When @command{nano} is run, this syntax will be automatically
activated if the current filename matches the extended regular
expression @var{fileregex}.  Or the syntax can be explicitly
activated by using the @option{-Y} or @option{--syntax}
command-line option followed by the @var{name}.

The @code{default} syntax is special: it takes no @var{fileregex},
and applies to files that don't match any syntax's @var{fileregex}.
The @code{none} syntax is reserved; specifying it on the
command line is the same as not having a syntax at all.

@item header "@var{regex}" @dots{}
If from all defined syntaxes no @var{fileregex} matched, then compare
this @var{regex} (or regexes) against the first line of the current file,
to determine whether this syntax should be used for it.

@item magic "@var{regex}" @dots{}
If no @var{fileregex} matched and no @code{header} regex matched
either, then compare this @var{regex} (or regexes) against the
result of querying the @code{magic} database about the current
file, to determine whether this syntax should be used for it.
(This functionality only works when @code{libmagic} is installed
on the system and will be silently ignored otherwise.)

@item linter @var{program} [@var{arg} @dots{}]
Use the given @var{program} to do a syntax check on the current file.
(This overrides the speller function.)

@item formatter @var{program} [@var{arg} @dots{}]
Use the given @var{program} to automatically reformat text ---
useful for a programming language like Go.
(This overrides the speller and linter functions.)

@item comment "@var{string}"
Use the given string for commenting and uncommenting lines.
If the string contains a vertical bar or pipe character (@t{|}),
this designates bracket-style comments; for example, @t{"/*|*/"} for
CSS files.  The characters before the pipe are prepended to the line and the
characters after the pipe are appended at the end of the line.  If no pipe
character is present, the full string is prepended; for example, @t{"#"} for
Python files.  If empty double quotes are specified, the comment/uncomment
functions are disabled; for example, @t{""} for JSON.
The default value is @t{"#"}.

@item color @var{fgcolor},@var{bgcolor} "@var{regex}" @dots{}
Display all pieces of text that match the
extended regular expression "regex" with foreground color "fgcolor" and
background color "bgcolor", at least one of which must be specified.
Valid colors for foreground and background are: white, black, red,
blue, green, yellow, magenta, and cyan.  You may use the prefix "bright"
to get a stronger color highlight for the foreground.  If your
terminal supports transparency, not specifying a "bgcolor" tells @command{nano}
to attempt to use a transparent background.

@item icolor @var{fgcolor},@var{bgcolor} "@var{regex}" @dots{}
Same as above, except that the matching is case insensitive.

@item color @var{fgcolor},@var{bgcolor} start="@var{fromrx}" end="@var{torx}"
Display all pieces of text whose start matches extended regular expression
"fromrx" and whose end matches extended regular expression "torx" with
foreground color "fgcolor" and background color "bgcolor", at least one of
which must be specified.  This means that, after an initial instance of
"fromrx", all text until the first instance of "torx" will be colored.
This allows syntax highlighting to span multiple lines.

@item icolor @var{fgcolor},@var{bgcolor} start="@var{fromrx}" end="@var{torx}"
Same as above, except that the matching is case insensitive.

@item include "@var{syntaxfile}"
Read in self-contained color syntaxes from "syntaxfile".  Note that
"syntaxfile" may contain only the above commands, from @code{syntax}
to @code{icolor}.

@item extendsyntax @var{name} @var{command} [@var{arg} @dots{}]
Extend the syntax previously defined as "@var{name}" with another @var{command}.
This allows you to add a new @code{color}, @code{icolor}, @code{header},
@code{magic}, @code{comment}, @code{linter}, or @code{formatter} command
to an already
defined syntax --- useful when you want to slightly improve a syntax defined
in one of the system-installed files (which normally are not writable).

@end table

@node Rebinding Keys
@section Rebinding Keys

Key bindings can be changed via the following three commands in a
nanorc file:

@table @code

@item bind key function menu
Rebinds @code{key} to @code{function} in the context of @code{menu}
(or in all menus where the function exists by using @code{all}).

@item bind key "string" menu
Makes @code{key} produce @code{string} in the context of @code{menu}
(or in all menus where the key exists when @code{all} is used).
The @code{string} can consist of text or commands or a mix of them.
(To enter a command into the @code{string}, precede its keystroke
with @kbd{M-V}.)

@item unbind key menu
Unbinds @code{key} from @code{menu}
(or from all menus where it exists by using @code{all}).

@end table

@sp 1
The format of @code{key} should be one of:

@itemize @w{}
@item
@code{^}@  followed by an ASCII character or the word "Space".
Example: @code{^C}.

@item
@code{M-}@  followed by a ASCII character or the word "Space".
Example: @code{M-C}.

@item
@code{F}@  followed by a numeric value from 1 to 16.
Example: @code{F10}.
@end itemize

@sp 1
Valid names for the @code{function} to be bound are:

@table @code

@item help
Invokes the help viewer.

@item cancel
Cancels the current command.

@item exit
Exits from the program (or from the help viewer or the file browser).

@item writeout
Writes the current buffer to disk, asking for a name.

@item savefile
Writes the current file to disk without prompting.

@item insert
Inserts a file into the current buffer (at the current cursor position),
or into a new buffer when option @code{multibuffer} is set.

@item whereis
Starts a forward search for text in the current buffer --- or for filenames
matching a string in the current list in the file browser.

@item wherewas
Starts a backward search for text in the current buffer.

@item searchagain
Repeats the last search command without prompting.

@item findprevious
As @code{searchagain}, but always in the backward direction.

@item findnext
As @code{searchagain}, but always in the forward direction.

@item replace
Interactively replaces text within the current buffer.

@item cut
Cuts and stores the current line (or the marked region).

@item copytext
Copies the current line (or the marked region) without deleting it.

@item uncut
Copies the currently stored text into the current buffer at the
current cursor position.

@item mark
Sets the mark at the current position, to start selecting text.

@item cutwordleft
Cuts from the cursor position to the beginning of the preceding word.

@item cutwordright
Cuts from the cursor position to the beginning of the next word.

@item cutrestoffile
Cuts all text from the cursor position till the end of the buffer.

@item curpos
Shows the current cursor position: the line, column, and character positions.

@item wordcount
Counts the number of words, lines and characters in the current buffer.

@item speller
Invokes a spell-checking program (or a linting program, if the current
syntax highlighting defines one).

@item justify
Justifies the current paragraph.

@item fulljustify
Justifies the entire current buffer.

@item indent
Indents (shifts to the right) the currently marked text.

@item unindent
Unindents (shifts to the left) the currently marked text.

@item comment
Comments or uncomments the current line or marked lines, using the comment
style specified in the active syntax.

@item complete
Completes the fragment before the cursor to a full word found elsewhere
in the current buffer.

@item left
Goes left one position (in the editor or browser).

@item right
Goes right one position (in the editor or browser).

@item up
Goes one line up (in the editor or browser).

@item down
Goes one line down (in the editor or browser).

@item scrollup
Scrolls the viewport up one row (meaning that the text slides down)
while keeping the cursor in the same text position, if possible.

@item scrolldown
Scrolls the viewport down one row (meaning that the text slides up)
while keeping the cursor in the same text position, if possible.

@item prevword
Moves the cursor to the beginning of the previous word.

@item nextword
Moves the cursor to the beginning of the next word.

@item home
Moves the cursor to the beginning of the current line.

@item end
Moves the cursor to the end of the current line.

@item beginpara
Moves the cursor to the beginning of the current paragraph.

@item endpara
Moves the cursor to the end of the current paragraph.

@item prevblock
Moves the cursor to the beginning of the current or preceding block of text.
(Blocks are separated by one or more blank lines.)

@item nextblock
Moves the cursor to the beginning of the next block of text.

@item pageup
Goes up one screenful.

@item pagedown
Goes down one screenful.

@item firstline
Goes to the first line of the file.

@item lastline
Goes to the last line of the file.

@item gotoline
Goes to a specific line (and column if specified).  Negative numbers count
from the end of the file (and end of the line).

@item findbracket
Moves the cursor to the bracket (brace, parenthesis, etc.) that matches
(pairs) with the one under the cursor.

@item prevbuf
Switches to editing/viewing the previous buffer when multiple buffers are open.

@item nextbuf
Switches to editing/viewing the next buffer when multiple buffers are open.

@item verbatim
Inserts the next keystroke verbatim into the file.

@item tab
Inserts a tab at the current cursor location.

@item enter
Inserts a new line below the current one.

@item delete
Deletes the character under the cursor.

@item backspace
Deletes the character before the cursor.

@item recordmacro
Starts the recording of keystrokes --- the keystrokes are stored
as a macro.  When already recording, the recording is stopped.

@item runmacro
Replays the keystrokes of the last recorded macro.

@item undo
Undoes the last performed text action (add text, delete text, etc).

@item redo
Redoes the last undone action (i.e., it undoes an undo).

@item refresh
Refreshes the screen.

@item suspend
Suspends the editor (if the suspending function is enabled, see the
"suspendenable" entry below).

@item casesens
Toggles case sensitivity in searching (search/replace menus only).

@item regexp
Toggles whether searching/replacing is based on literal strings or regular expressions.

@item backwards
Toggles whether searching/replacing goes forward or backward.

@item prevhistory
Shows the previous history entry in the prompt menus (e.g.@: search).

@item nexthistory
Shows the next history entry in the prompt menus (e.g.@: search).

@item flipreplace
Toggles between searching for something and replacing something.

@item flipgoto
Toggles between searching for text and targeting a line number.
(The form @code{gototext} is deprecated.)

@item flipexecute
Toggles between inserting a file and executing a command.

@item flipnewbuffer
Toggles between inserting into the current buffer and into a new
empty buffer.

@item dosformat
When writing a file, switches to writing a DOS format (CR/LF).

@item macformat
When writing a file, switches to writing a Mac format.

@item append
When writing a file, appends to the end instead of overwriting.

@item prepend
When writing a file, 'prepends' (writes at the beginning) instead of overwriting.

@item backup
When writing a file, creates a backup of the current file.

@item discardbuffer
When about to write a file, discard the current buffer without saving.
(This function is bound by default only when option @option{--tempfile}
is in effect.)

@item browser
Starts the file browser, allowing to select a file from a list.

@item gotodir
Goes to a directory to be specified, allowing to browse anywhere
in the filesystem.

@item firstfile
Goes to the first file when using the file browser (reading or writing files).

@item lastfile
Goes to the last file when using the file browser (reading or writing files).

@item nohelp
Toggles the presence of the two-line list of key bindings at the bottom of the screen.

@item constupdate
Toggles the constant display of the current line, column, and character positions.

@item morespace
Toggles the presence of the blank line that 'separates' the title bar from the file text.

@item smoothscroll
Toggles smooth scrolling (when moving around with the arrow keys).

@item softwrap
Toggles the displaying of overlong lines on multiple screen lines.

@item whitespacedisplay
Toggles the showing of whitespace.

@item nosyntax
Toggles syntax highlighting.

@item smarthome
Toggles the smartness of the Home key.

@item autoindent
Toggles whether new lines will contain the same amount of whitespace as the preceding line.

@item cuttoend
Toggles whether cutting text will cut the whole line or just from the current cursor
position to the end of the line.

@item nowrap
Toggles whether long lines will be hard-wrapped to the next line.

@item tabstospaces
Toggles whether typed tabs will be converted to spaces.

@item backupfile
Toggles whether a backup will be made of the file to be edited.

@item multibuffer
Toggles whether a file is inserted into the current buffer
or read into a new buffer.

@item mouse
Toggles mouse support.

@item noconvert
Toggles automatic conversion of files from DOS/Mac format.

@item suspendenable
Toggles whether the suspend shortcut (normally @kbd{^Z}) will suspend the editor.

@end table

@sp 1
Valid names for @code{menu} are:

@table @code

@item main
The main editor window where text is entered and edited.

@item search
The search menu (AKA whereis).

@item replace
The 'search to replace' menu.

@item replacewith
The 'replace with' menu, which comes up after 'search to replace'.

@item gotoline
The 'goto line (and column)' menu.

@item writeout
The 'write file' menu.

@item insert
The 'insert file' menu.

@item extcmd
The menu for inserting output from an external command, reached from the insert menu.

@item help
The help-viewer menu.

@item spell
The interactive spell checker Yes/no menu.

@item linter
The linter menu.

@item browser
The file browser for inserting or writing a file.

@item whereisfile
The 'search for a file' menu in the file browser.

@item gotodir
The 'go to directory' menu in the file browser.

@item all
A special name that encompasses all menus.  For @code{bind} it means
all menus where the specified @code{function} exists; for @code{unbind}
it means all menus where the specified @code{key} exists.

@end table


@node The File Browser
@chapter The File Browser

When reading or writing files, pressing @kbd{^T} will invoke the file browser.
Here, one can navigate directories in a graphical manner in order to
find the desired file.

Basic movement in the file browser is accomplished with the arrow keys,
page up, and page down.  More advanced movement is accomplished by
searching via @kbd{^W} (or @kbd{w'} and changing directories via
@kbd{^_} (or @kbd{g}).  The behavior of the @kbd{Enter} key (or @kbd{s})
varies by what is currently selected.
If the currently selected object is a directory, the file browser will
enter and display the contents of the directory.  If the object is a
file, this filename and path are copied to the status bar, and the file
browser exits.


@node Pico Compatibility
@chapter Pico Compatibility

@command{nano} attempts to emulate Pico as closely as possible, but there
are some differences between the editors:

@table @code

@item Interactive Replace
Instead of allowing you to replace either just one occurrence of a search
string or all of them, @command{nano}'s replace function is interactive: it
will pause at each found search string and query whether to replace this
instance.  You can then choose Yes, or No (skip this one), or All (don't
ask any more), or Cancel (stop with replacing).

@item Search and Replace History
When the option @option{-H} or @option{--historylog} is given (or set in
the a nanorc file), text entered as search or replace strings is stored.
These strings can be accessed with the up/down arrow keys, or you can
type the first few characters and then use @kbd{Tab} to cycle through the
matching strings.  A retrieved string can subsequently be edited.

@item Position History
When the option @option{-P} or @option{--positionlog} is given (or set in
a nanorc file), @command{nano} will store the position of the cursor
when you close a file, and will place the cursor in that position
again when you later reopen the file.

@item Current Cursor Position
The output of the "Display Cursor Position" command (@kbd{^C}) displays
not only the current line and character position of the cursor,
but also (between the two) the current column position.

@item Spell Checking
In the internal spell checker misspelled words are sorted alphabetically
and trimmed for uniqueness, such that the words 'apple' and 'Apple' will
be prompted for correction separately.

@item Writing Selected Text to Files
When using the Write-Out key (@kbd{^O}), text that has been selected using the
marking key (@kbd{^^}) can not just be written out to a new (or existing) file,
it can also be appended or prepended to an existing file.

@item Reading Text from a Command
When using the Read-File key (@kbd{^R}), @command{nano} can not just read a file,
it can also read the output of a command to be run (@kbd{^X}).

@item Reading from Working Directory
By default, Pico will read files from the user's home directory (when
using @kbd{^R}), but it will write files to the current working directory
(when using @kbd{^O}).  @command{nano} makes this symmetrical: always reading
from and writing to the current working directory --- the directory
that @command{nano} was started in.

@item File Browser
In the file browser, @command{nano} does not implement the Add, Copy,
Rename, and Delete commands that Pico provides.  In @command{nano} the
browser is just a file browser, not a file manager.

@item Toggles
Many options which alter the functionality of the program can be
"toggled" on or off using Meta key sequences, meaning the program does
not have to be restarted to turn a particular feature on or off.
@xref{Feature Toggles} for a list of options that can be toggled.
Or see the list at the end of the main internal help text (@kbd{^G}) instead.

@end table


@node Building and Configure Options
@chapter Building and Configure Options

Building @command{nano} from source is fairly straightforward if you are
familiar with compiling programs with autoconf support:

@iftex
@sp 1
@end iftex
@example
  tar xvzf nano-x.y.z.tar.gz
  cd nano-x.y.z
  ./configure
  make
  make install
@end example
@iftex
@sp 1
@end iftex

The possible options to @code{./configure} are:

@table @code

@item --disable-browser
Disable the mini file browser that can be called with @kbd{^T} when reading
or writing files.

@item --disable-color
Disable support for the syntax coloring of files.  This also eliminates
the @option{-Y} command-line option, which chooses a specific syntax.

@item --disable-comment
Disable the single-keystroke comment/uncomment function (@kbd{M-3}).

@item --disable-extra
Disable the Easter egg: a crawl of major contributors.

@item --disable-help
Disable the help function.  Doing this makes the binary much smaller,
but makes it difficult for new users to learn more than very basic
things about using the editor.

@item --disable-histories
Disable the code for the handling of the history files: the search and
replace strings that were used, and the cursor position at which each
file was closed.  This also eliminates the @option{-H} and @option{-P}
command-line options, which switch on the logging of search/replace
strings and cursor positions.

@item --disable-justify
Disable the justify and unjustify functions.

@item --disable-libmagic
Disable the use of the library of magic-number tests (for determining
the file type and thus which syntax to use for colouring --- often the
tests on filename extension and header line will be enough).

@item --disable-linenumbers
Disable the line-numbering function (@kbd{M-#}).  This also eliminates the
@option{-l} command-line option, which turns line numbering on.

@item --disable-mouse
Disable all mouse functionality.  This also eliminates the @option{-m}
command-line option, which enables the mouse functionality.

@item --disable-multibuffer
Disable support for opening multiple files at a time and switching
between them on the fly.  This also eliminates the @option{-F} command-line
option, which causes a file to be read into a separate buffer by default.

@item --disable-nanorc
Disable support for reading the nanorc files at startup.  With such
support, you can store custom settings in a system-wide and a per-user
nanorc file rather than having to pass command-line options to get
the desired behavior.  @xref{Nanorc Files} for more info.
Disabling this also eliminates the @option{-I} command-line option,
which inhibits the reading of nanorc files.

@item --disable-operatingdir
Disable setting the operating directory.  This also eliminates the @option{-o}
command-line option, which sets the operating directory.

@item --disable-speller
Disable use of the spell checker.  This also eliminates the @option{-s}
command-line option, which allows specifying an alternate spell checker.

@item --disable-tabcomp
Disable tab completion (when nano asks for a filename or a search string).

@item --disable-wordcomp
Disable word completion (@kbd{^]}).

@item --disable-wrapping
Disable all hard-wrapping of overlong lines.  This also eliminates the
@option{-w} command-line option, which switches long-line wrapping off.

@item --enable-tiny
This option implies all of the above.  It also disables some other
internals of the editor, like the marking code, the cut-to-end-of-line
code, and the function toggles.  By using the enabling
counterpart of the above options together with @option{--enable-tiny},
specific features can be switched back on --- but a few cannot.

@item --enable-debug
Enable support for runtime debug output.  This can get pretty messy, so
chances are you only want this feature when you're working on the nano source.

@item --disable-nls
Disables Native Language support.  This will disable the use of any
available GNU @command{nano} translations.

@item --disable-wrapping-as-root
Disable hard-wrapping of overlong lines by default when @command{nano}
is run as root.

@item --enable-utf8
Enable support for reading and writing Unicode files.  This will require
either a wide version of curses, or a UTF-8-enabled version of Slang.

@item --disable-utf8
Disable support for reading and writing Unicode files.  Normally the
configure script auto-detects whether to enable UTF-8 support or not.
You can use this or the previous option to override that detection.

@item --enable-altrcname=@var{name}
Use the file with the given @var{name} (in the user's home directory)
as nano's settings file, instead of the default @code{.nanorc}.

@item --with-slang
Compile @command{nano} against Slang instead of against ncurses or other
curses libraries.

@end table

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