Difference between revisions of "Nano"

Revision as of 12:19, 25 February 2014

GNU nano (or nano) is a text editor which aims to introduce a simple interface and intuitive command options to console based text editing. nano is the default console editor in distributions such as Ubuntu and supports features including colorized syntax highlighting, DOS/Mac file type conversions, spellchecking and UTF-8 encoding. nano opened with an empty buffer typically occupies under 1.5 MB of resident memory. nano Screenshot.

Package installation

You can install the nano package from the official repositories. It is likely that is already on your system, as it is included in the base group.

Configuration

Creating ~/.nanorc

The look, feel and function of nano is typically controlled by way of either command-line arguments, or configuration commands within the file ~/.nanorc.
A sample configuration file is installed upon program installation and is located at /etc/nanorc. To customize your nano configuration, first create a local copy at ~/.nanorc:

$ cp /etc/nanorc ~/.nanorc

Proceed to establish the nano console environment by setting and/or unsetting commands within ~/.nanorc file.

Syntax highlighting

for PKGBUILD files

This new version highlights like the Arch Linux "svntogit-server".

# Arch PKGBUILD files
#
syntax "pkgbuild" "^.*PKGBUILD*"
# commands
color red "\<(cd|echo|enable|exec|export|kill|popd|pushd|read|source|touch|type)\>"
color brightblack "\<(case|cat|chmod|chown|cp|diff|do|done|elif|else|esac|exit|fi|find|for|ftp|function|grep|gzip|if|in)\>"
color brightblack "\<(install|ln|local|make|mv|patch|return|rm|sed|select|shift|sleep|tar|then|time|until|while|yes)\>"
# ${*}
icolor blue "\$\{?[0-9A-Z_!@#$*?-]+\}?"
# numerics
color blue "\ [0-9]*"
color blue "\.[0-9]*"
color blue "\-[0-9]*"
color blue "=[0-9]"
# spaces
color ,green "[[:space:]]+$"
# strings; multilines are not supported
color brightred ""(\\.|[^"])*"" "'(\\.|[^'])*'"
# comments
color brightblack "#.*$"

This is another version from this forum thread.

## Arch PKGBUILD files
##
syntax "pkgbuild" "^.*PKGBUILD$"
color green start="^." end="$"
color cyan "^.*(pkgbase|pkgname|pkgver|pkgrel|pkgdesc|arch|url|license).*=.*$"
color brightcyan "\<(pkgbase|pkgname|pkgver|pkgrel|pkgdesc|arch|url|license)\>"
color brightcyan "(\$|\$\{|\$\()(pkgbase|pkgname|pkgver|pkgrel|pkgdesc|arch|url|license)(|\}|\))"
color cyan "^.*(depends|makedepends|optdepends|conflicts|provides|replaces).*=.*$"
color brightcyan "\<(depends|makedepends|optdepends|conflicts|provides|replaces)\>"
color brightcyan "(\$|\$\{|\$\()(depends|makedepends|optdepends|conflicts|provides|replaces)(|\}|\))"
color cyan "^.*(groups|backup|noextract|options).*=.*$"
color brightcyan "\<(groups|backup|noextract|options)\>"
color brightcyan "(\$|\$\{|\$\()(groups|backup|noextract|options)(|\}|\))"
color cyan "^.*(install|source|md5sums|sha1sums|sha256sums|sha384sums|sha512sums).*=.*$"
color brightcyan "\<(install|source|md5sums|sha1sums|sha256sums|sha384sums|sha512sums)\>"
color brightcyan "(\$|\$\{|\$\()(install|source|md5sums|sha1sums|sha256sums|sha384sums|sha512sums)(|\}|\))"
color brightcyan "\<(startdir|srcdir|pkgdir)\>"
color cyan "\.install"
color brightwhite "=" "'" "\(" "\)" "\"" "#.*$" "\," "\{" "\}"
color brightred "build\(\)"
color brightred "package_.*.*$"
color brightred "\<(configure|make|cmake|scons)\>"
color red "\<(DESTDIR|PREFIX|prefix|sysconfdir|datadir|libdir|includedir|mandir|infodir)\>"

Save this file as (for example) /etc/nano/pkgbuild.nanorc.

Then include the file in your ~/.nanorc or to /etc/nanorc by adding the following line:

include "/etc/nano/pkgbuild.nanorc"

Other definitions

Syntax highlighting enhancements which replace and expand the defaults can be found in the AUR, nano-syntax-highlighting-git^AUR.

Suggested configuration

Suspension

Unlike most interactive programs, suspension is not enabled by default. To change this, uncomment the 'set suspend' line in /etc/nanorc. This will allow you to use the keys Ctrl+z to send nano to the background.

Do not wrap text

If you are coming from another distribution, you might wonder about nano's strange behaviour, so just edit /etc/nanorc like this:

## Do not wrap text at all.
set nowrap

nano usage

Special functions

• Ctrl key modified shortcuts (^) representing commonly used functions are listed along the bottom two lines of the nano screen.
• Additional functions can be interactively toggled by way of Meta (typically Alt) and/or Esc key modified sequences.

Shortcut lists overview

• ^G Get Help (F1)

Displays the online help files within the session window. A suggested read for nano users of all levels

• ^O WriteOut (F3)

Save the contents of the current file buffer to a file on the disk

• ^R Read File (F5)

Inserts another file into the current one at the cursor location

• ^Y Prev Page (F7)

Display the previous buffered screen

• ^K Cut Text (F9)

Cut and store the current line from the beginning of the line to the end of the line

• ^C Cur Pos (F11)

Display line, column and character position information at the current location of the cursor

• ^X Exit (F2)

Close and exit nano

• ^J Justify (F4)

Aligns text according to the geometry of the console window

• ^W Where (F6)

Perform a case-insensitive string, or regular expression search

• ^V Next Page (F8)

Display the next buffered screen

• ^U UnCut Text (F10)

Paste the contents of the cut buffer to the current cursor location

• ^T To Spell (F12)

Spellcheck the contents of the buffer with the built-in spell, if available

Selected toggle functions

• Meta+c (or Esc+c)

Toggles support for line, column and character position information.

• Meta+i (or Esc+i)

Toggles support for the auto indentation of lines

• Meta+k (or Esc+k)

Toggles support for cutting text from the current cursor position to the end of the line

• Meta+m (or Esc+m)

Toggles mouse support for cursor placement, marking and shortcut execution

• Meta+x (or Esc+x)

Toggles the display of the shortcut list at the bottom of the nano screen for additional screen space

Tips & tricks

Replacing vi with nano

Casual users may prefer the use of nano over vi for its simplicity and ease of use and may opt to replace vi with nano as the default text editor for commands such as visudo.

Method one

sudo from the core repository is compiled with --with-env-editor by default and honors the use of the VISUAL and EDITOR variables. To establish nano as the visudo editor for the duration of the current shell session, set and export the EDITOR variable before calling visudo.

export EDITOR=nano 

Example usage

 export EDITOR=nano && sudo visudo

Method two

The EDITOR variable can also be set within the following files for persistent use:

• ~/.bash_profile (login shell)
• ~/.profile (instead of `.bash_profile` ; see Environment Variables
• ~/.bashrc (interactive, non-login shell)
• /etc/profile (global settings for all system users except root)

Example .bash_profile

. $HOME/.bashrc

Method three

Symbolic linking

As root, or with su -

Rename the vi executable to vi.old for ease of restoration:

# mv /usr/bin/vi /usr/bin/vi.old

Create a symbolic link from /usr/bin/nano to /usr/bin/vi

# ln -s /usr/bin/nano /usr/bin/vi

Assuming sudo is installed and properly configured. You will need to add vi to the IgnorePkg list in pacman.conf to make this permanent. Otherwise it will revert back to vi the next time it is updated.

Restoration of vi

Remove the /usr/bin/vi symbolic link:

unlink /usr/bin/vi

Rename the vi.old executable back to vi:

mv /usr/bin/vi.old /usr/bin/vi

Method four

Removal & symbolic linking

Use pacman to remove the vi package, its configuration, and all unneeded dependencies:

pacman -Rns vi

Create a symbolic link from /usr/bin/nano to /usr/bin/vi:

ln -s /usr/bin/nano /usr/bin/vi

Restoration of vi

Remove the /usr/bin/vi symbolic link:

unlink /usr/bin/vi

Use pacman to install the previously deinstallled vi package:

pacman -S vi

Additional resources

• nano (text editor) - Wikipedia Entry
• GNU nano Homepage - Official Site
• GNU nano Bugs Bug Reporting
• Better syntax highlighting definitions