nano/doc/nano.texi

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

@smallbook
@set EDITION 0.4
@set VERSION 2.7.3
@set UPDATED December 2016

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

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

@titlepage
@title GNU @code{nano}
@subtitle a small and friendly text editor.
@subtitle version 2.7.3

@author Chris Allegretta
@page

This manual documents GNU @code{nano}, a small and friendly text editor.

This manual is part of the GNU @code{nano} distribution.@*
@sp 4
Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
2009, 2014, 2015 Free Software Foundation, Inc.

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

* 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 <http://www.gnu.org/licenses/>.

* 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 <http://www.gnu.org/licenses/>.

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


@node Top
@top

This manual documents GNU @code{nano}, a small and friendly text editor.

@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


@node Introduction
@chapter Introduction

GNU @code{nano} is a small and friendly text editor.  Besides basic text
editing, @code{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 @code{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.  See
@xref{Pico Compatibility}, for more info.

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


@node Invoking
@chapter Invoking

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

@quotation
@code{nano [FILE]}
@end quotation

But it is also possible to specify one or more options, 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 the complete command synopsis is:

@quotation
@code{nano [OPTION]@dots{} [[+LINE[,COLUMN]|+,COLUMN] FILE]@dots{}}
@end quotation

But normallly you would set your preferred options in your
@file{.nanorc} file.  And when the @code{positionlog} option is set
(making @code{nano} remember the cursor position when you close a file),
you will rarely need to specify a line number.


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

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

@table @option

@item +@var{line},@var{column}
Start at line number @var{line} and column number @var{column} (at least one of
which must be specified) instead of the default of line 1, column 1.

@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
Log search and replace strings to @file{~/.nano/search_history},
so they can be retrieved in later sessions.

@item -I
@itemx --ignorercfiles
Don't look at the system's nanorc file nor at the user's @file{~/.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 -N
@itemx --noconvert
Disable automatic conversion of files from DOS/Mac format.

@item -O
@itemx --morespace
Use the blank line below the titlebar 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.
(The old form of this option, @code{--poslog}, is deprecated.)

@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 statusbar blanking.  Statusbar 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 a specific syntax from the nanorc files to use for highlighting.
See @xref{Syntax Highlighting}, for more info.

@item -c
@itemx --constantshow
Constantly display the cursor position and line number on the statusbar.
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 --cut
Make the 'Cut Text' command (normally ^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 ^Q (XON) and ^S (XOFF) sequences so data being sent to the
editor can be stopped and started.

@item -q
@itemx --quiet
Do not report errors in the nanorc file nor ask them to be acknowledged
by pressing Enter at startup.

@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.

@item -s @var{program}
@itemx --speller=@var{program}
Invoke the given program as the spell checker.  By default, @command{nano}
uses the command specified in the @env{SPELL} environment variable, or,
if @env{SPELL} is not set, its own interactive spell checker that requires
the @command{spell} program to be installed on your system.

@item -t
@itemx --tempfile
Don't ask whether to save a modified buffer when exiting with ^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 @code{--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 statusbar 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 ^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 -a
@itemx -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::
* Limitation::
@end menu

@node Entering Text
@section Entering Text

@code{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 000 to 255) will make @code{nano} behave as if you typed the key
with that value.

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

For example, typing "Esc Esc 2 3 4" will enter the character "ê" ---
useful when going to a French party.  Typing "M-V 0 0 2 5 c 6" will
enter the symbol "◆", a little black diamond.

@node Commands
@section Commands

Commands are given by using the Control key (Ctrl, shown as @code{^})
or the Meta key (Alt or Cmd, shown as @code{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: ^K).  The cut line is stored in the cutbuffer.
Consecutive strokes of ^K will add each cut line to this buffer, but a ^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: ^U).

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

@node The Mark
@section The Mark

Text can be selected by first 'setting the Mark' (default key bindings:
^6 and 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 in
reverse video (or in bold if you set the boldtext option).
This selection can now be cut or copied in its entirety with a single
^K or M-6.  Or the selection can be used to limit the scope of a
search-and-replace (^\) or spell-checking session (^T).

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

@node Screen Layout
@section Screen Layout

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

The titlebar consists of
three sections: left, center and right.  The section on the left
displays the version of @code{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 statusbar 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 statusbar.  Any questions
that are asked of the user will be asked on the statusbar, and any user
input (search strings, filenames, etc.) will be input on the statusbar.

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: ^W).  The default search
mode is forward, case-insensitive, and for literal strings.  But one
can search backwards by pressing M-B, search case sensitively with M-C,
and interpret regular expressions in the search string with M-R.

A regular expression in a search string always covers just one line;
it cannot span multiple lines.  And when replacing (with ^\ or 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 Limitation
@section Limitation

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


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

The built-in help system in @code{nano} is available by pressing ^G@.
It is fairly self-explanatory.  It documents the various parts of the
editor and the available keystrokes.  Navigation is via the ^Y (Page Up)
and ^V (Page Down) keys.  ^X exits 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 (see @xref{Commands}, for more info).
The following global toggles are available:

@table @code

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

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

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

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

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

@item Cut To End Toggle (Meta-K)
toggles the @code{-k} (@code{--cut}) command-line option.

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

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

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

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

@item Whitespace Display Toggle (Meta-P)
toggles the whitespace-display mode.
See @xref{Whitespace}, for more info.

@item Tabs to Spaces Toggle (Meta-Q)
toggles the @code{-E} (@code{--tabstospaces}) command-line option.

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

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

@item Color Syntax Highlighting Toggle (Meta-Y)
toggles color syntax highlighting if you have color syntaxes in your
nanorc.  See @xref{Syntax Highlighting}, for more info.

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

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

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

@end table


@node Nanorc Files
@chapter Nanorc Files

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

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

Options in nanorc files take precedence over @code{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 @file{~/.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 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 "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 @code{--backup} or @code{-B}.
The uniquely numbered files are stored in the specified directory.

@item set backwards
Do backwards searches by default.

@item set boldtext
Use bold instead of reverse video for the titlebar, statusbar, key combos,
and selected text.  This can be overridden for the first three by setting
the options @code{titlecolor}, @code{statuscolor}, and @code{keycolor}.

@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 in the status bar.
(The old form of this option, @code{set const}, is deprecated.)

@item set cut
Use cut-to-end-of-line by default, instead of cutting the whole line.

@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}.

@item set functioncolor @var{fgcolor},@var{bgcolor}
Specify the color combination to use for the function descriptions
in the two help lines at the bottom of the screen.
See @code{set titlecolor} for more details.

@item set historylog
Enable the use of @file{~/.nano/search_history} for saving and reading
search/replace strings.

@item set justifytrim
When justifying text, trailing whitespace will automatically be removed.

@item set keycolor @var{fgcolor},@var{bgcolor}
Specify the color combination to use for the shortcut key combos
in the two help lines at the bottom of the screen.
See @code{set titlecolor} for more details.

@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 titlebar 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 ^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 nonewlines
Don't add newlines to the ends of files.

@item set nowrap
Don't hard-wrap text at all.

@item set numbercolor @var{fgcolor},@var{bgcolor}
Specify the color combination to use for line numbers.
See @code{set titlecolor} for more details.

@item set operatingdir "directory"
@code{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.
(The old form of this option, @code{set poslog}, is deprecated.)

@item set preserve
Preserve the XON and XOFF keys (^Q and ^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 statusbar blanking.  Statusbar messages will disappear after 1
keystroke instead of 25.

@item set quiet
When set, @code{nano} will not report errors in the nanorc file nor ask them
to be acknowledged by pressing Enter at startup.  If this option is used, it
should be placed at the top of the file to be fully effective.

@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 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 "spellprog"
Use spelling checker "spellprog" instead of the built-in one, which
calls "spell".

@item set statuscolor @var{fgcolor},@var{bgcolor}
Specify the color combination to use for the statusbar.
See @code{set titlecolor} for more details.

@item set suspend
Allow @code{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}
Specify the color combination to use for the titlebar.
Valid color names for foreground and background are:
white, black, blue, green, red, cyan, yellow, and magenta.
The name of the foreground color may be prefixed with 'bright'.
And either @var{fgcolor} or @var{,bgcolor} may be left out.

@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 @code{nano}.

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

@table @code

@item syntax "str" ["fileregex" @dots{}]
Defines a syntax named "str" which can be activated via the @code{-Y/--syntax}
command-line option, or will be automatically activated if the current
filename matches the extended regular expression "fileregex".  All
subsequent @code{color}, @code{icolor}, @code{header} and other such
statements will apply to this "str" syntax until a new @code{syntax}
command is encountered.

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

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

@item formatter program [arg @dots{}]
Use the given program to automatically reformat text.
Useful in certain programming languages (e.g.@: Go).

@item header "regex" @dots{}
Add one or more regexes which will
be compared against the very first line of the file to be edited,
to determine whether this syntax should be used for that file.

@item magic "regex" @dots{}
Add one or more regexes which will be
compared against the result of querying the magic database about the file
to be edited, to determine whether this syntax should be used for that
file.  This functionality only works when libmagic is installed on the
system and will be silently ignored otherwise.

@item comment "string"
Use the given string for commenting and uncommenting lines.  A vertical bar or
pipe character (|) designates bracket-style comments; for example, "/*|*/" 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 entire string is prepended; for example, "#" for
Python files.  If empty double quotes are specified, the comment/uncomment
functions are disabled; for example, "" for JSON.  Double quotes or backslashes
may be escaped with a backslash; for example, ".\\"" for man page source.

@item color fgcolor,bgcolor "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 @code{nano}
to attempt to use a transparent background.

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

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

@item icolor fgcolor,bgcolor start="sr" end="er"
Same as above, except that the text matching is case insensitive.

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

@end table

@node Rebinding Keys
@section Rebinding Keys

Key bindings can be changed via the following two 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 unbind key menu
Unbinds @code{key} from @code{menu}
(or from all menus where it exists by using @code{all}).

@end table

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

@table @code

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

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

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

@end table

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 or warning.

@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
Searches for text in the current buffer --- or for filenames matching
a string in the current list in the file browser

@item searchagain
Repeats the last search command without prompting.
(The form 'research' is deprecated.)

@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.
(The form 'cursorpos' is deprecated.)

@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 up one line of text from the current position.

@item scrolldown
Scrolls down one line of text from the current position.

@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 prevpage
Goes up one screenful.

@item nextpage
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 gototext
Switches from targeting a line number to searching for text.

@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 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.
(The form 'regex' is deprecated.)

@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.
(The form 'dontreplace' 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.
(The form 'newbuffer' is deprecated.)

@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 tofiles
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 which 'separates' the titlebar 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 sequence (normally ^Z) will suspend the editor window.

@end table

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'.
(The form 'replace2' is deprecated.)

@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 ^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 ^W (or 'w') and changing directories via ^_ (or 'g').  The
behavior of the Enter (or 's') key 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 statusbar, and the file
browser exits.


@node Pico Compatibility
@chapter Pico Compatibility

@code{nano} attempts to emulate Pico as closely as possible, but there
are certain 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, @code{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 @code{-H} or @code{--historylog} is given (or set in
the .nanorc file), text entered as search or replace strings is stored.
These strings can be accessed with the up/down arrow keys.  A retrieved
string can subsequently be edited.

@item Writing, Appending, or Prepending Selected Text to Files
Text selected using the marking key (^^) can be written out, appended,
or prepended to a new or existing file using the WriteOut key (^O).

@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.
See the internal help function (^G) for a list of features that
can be toggled.  Or see @xref{Feature Toggles} instead.

@item Current Cursor Position
The output of the "Display Cursor Position" command (^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.

@end table


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

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

@itemize @bullet
@item tar xvfz nano-x.y.z.tar.gz (where x.y.z is the version of
@code{nano})
@item cd nano-x.y.z/
@item ./configure
@item make
@item make install
@end itemize

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

@table @code

@item --disable-browser
Disable the mini file browser when reading or writing files.

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

@item --disable-extra
Disable extra features.  At the moment, this is just easter-egg-type
stuff.

@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 @code{-H} and @code{-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-mouse
Disable all mouse functionality.  This also eliminates the @code{-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 @code{-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.  See @xref{Nanorc Files}, for more info.
Disabling this also eliminates the @code{-I} and @code{-q} command-line
options; the first inhibits the reading of nanorcfiles, and the second
suppresses warnings about errors in those files.

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

@item --disable-speller
Disable use of the spell checker.  This also eliminates the @code{-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.

@item --disable-wrapping
Disable all hard-wrapping of overlong lines.  This also eliminates the
@code{-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 @code{--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 @code{nano} translations.

@item --disable-wrapping-as-root
Disable hard-wrapping of overlong lines by default when @code{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 @code{nano} against Slang instead of against ncurses or other
curses libraries.

@end table

@contents
@bye