XiT v2.2 for OS/2 serial key or number

This module provides access to some variables used or maintained by the interpreter and to functions that interact strongly with the interpreter. It is always available.

¶

The list of command line arguments passed to a Python script. is the script name (it is operating system dependent whether this is a full pathname or not). If the command was executed using the command line option to the interpreter, is set to the string . If no script name was passed to the Python interpreter, is the empty string.

To loop over the standard input, or the list of files given on the command line, see the module.

¶

An indicator of the native byte order. This will have the value on big-endian (most-significant byte first) platforms, and on little-endian (least-significant byte first) platforms.

¶

A tuple of strings giving the names of all modules that are compiled into this Python interpreter. (This information is not available in any other way — only lists the imported modules.)

(func, args)¶

Call , while tracing is enabled. The tracing state is saved, and restored afterwards. This is intended to be called from a debugger from a checkpoint, to recursively debug some other code.

¶

A string containing the copyright pertaining to the Python interpreter.

()¶

Clear the internal type cache. The type cache is used to speed up attribute and method lookups. Use the function only to drop unnecessary references during reference leak debugging.

This function should be used for internal and specialized purposes only.

()¶

Return a dictionary mapping each thread’s identifier to the topmost stack frame currently active in that thread at the time the function is called. Note that functions in the module can build the call stack given such a frame.

This is most useful for debugging deadlock: this function does not require the deadlocked threads’ cooperation, and such threads’ call stacks are frozen for as long as they remain deadlocked. The frame returned for a non-deadlocked thread may bear no relationship to that thread’s current activity by the time calling code examines the frame.

This function should be used for internal and specialized purposes only.

¶

Integer specifying the handle of the Python DLL. Availability: Windows.

(value)¶

If value is not , this function prints it to , and saves it in .

is called on the result of evaluating an expression entered in an interactive Python session. The display of these values can be customized by assigning another one-argument function to .

¶

If this is true, Python won’t try to write or files on the import of source modules. This value is initially set to or depending on the command line option and the environment variable, but you can set it yourself to control bytecode file generation.

(type, value, traceback)¶

This function prints out a given traceback and exception to .

When an exception is raised and uncaught, the interpreter calls with three arguments, the exception class, exception instance, and a traceback object. In an interactive session this happens just before control is returned to the prompt; in a Python program this happens just before the program exits. The handling of such top-level exceptions can be customized by assigning another three-argument function to .

¶

¶

These objects contain the original values of and at the start of the program. They are saved so that and can be restored in case they happen to get replaced with broken objects.

()¶

This function returns a tuple of three values that give information about the exception that is currently being handled. The information returned is specific both to the current thread and to the current stack frame. If the current stack frame is not handling an exception, the information is taken from the calling stack frame, or its caller, and so on until a stack frame is found that is handling an exception. Here, “handling an exception” is defined as “executing or having executed an except clause.” For any stack frame, only information about the most recently handled exception is accessible.

If no exception is being handled anywhere on the stack, a tuple containing three values is returned. Otherwise, the values returned are . Their meaning is: type gets the exception type of the exception being handled (a class object); value gets the exception parameter (its associated value or the second argument to , which is always a class instance if the exception type is a class object); traceback gets a traceback object (see the Reference Manual) which encapsulates the call stack at the point where the exception originally occurred.

If is called, this function will return three values until either another exception is raised in the current thread or the execution stack returns to a frame where another exception is being handled.

Warning

Assigning the traceback return value to a local variable in a function that is handling an exception will cause a circular reference. This will prevent anything referenced by a local variable in the same function or by the traceback from being garbage collected. Since most functions don’t need access to the traceback, the best solution is to use something like to extract only the exception type and value. If you do need the traceback, make sure to delete it after use (best done with a … statement) or to call in a function that does not itself handle an exception.

Note

Beginning with Python 2.2, such cycles are automatically reclaimed when garbage collection is enabled and they become unreachable, but it remains more efficient to avoid creating cycles.

()¶

This function clears all information relating to the current or last exception that occurred in the current thread. After calling this function, will return three values until another exception is raised in the current thread or the execution stack returns to a frame where another exception is being handled.

This function is only needed in only a few obscure situations. These include logging and error handling systems that report information on the last or current exception. This function can also be used to try to free resources and trigger object finalization, though no guarantee is made as to what objects will be freed, if any.

¶

¶

¶

Deprecated since version 1.5: Use instead.

Since they are global variables, they are not specific to the current thread, so their use is not safe in a multi-threaded program. When no exception is being handled, is set to and the other two are undefined.

¶

A string giving the site-specific directory prefix where the platform-dependent Python files are installed; by default, this is also . This can be set at build time with the argument to the configure script. Specifically, all configuration files (e.g. the header file) are installed in the directory , and shared library modules are installed in , where X.Y is the version number of Python, for example .

¶

A string giving the absolute path of the executable binary for the Python interpreter, on systems where this makes sense. If Python is unable to retrieve the real path to its executable, will be an empty string or .

([arg])¶

Exit from Python. This is implemented by raising the exception, so cleanup actions specified by finally clauses of statements are honored, and it is possible to intercept the exit attempt at an outer level.

The optional argument arg can be an integer giving the exit status (defaulting to zero), or another type of object. If it is an integer, zero is considered “successful termination” and any nonzero value is considered “abnormal termination” by shells and the like. Most systems require it to be in the range 0–127, and produce undefined results otherwise. Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors. If another type of object is passed, is equivalent to passing zero, and any other object is printed to and results in an exit code of 1. In particular, is a quick way to exit a program when an error occurs.

Since ultimately “only” raises an exception, it will only exit the process when called from the main thread, and the exception is not intercepted.

¶

This value is not actually defined by the module, but can be set by the user (or by a program) to specify a clean-up action at program exit. When set, it should be a parameterless function. This function will be called when the interpreter exits. Only one function may be installed in this way; to allow multiple functions which will be called at termination, use the module.

Note

The exit function is not called when the program is killed by a signal, when a Python fatal internal error is detected, or when is called.

Deprecated since version 2.4: Use instead.

¶

The struct sequence flags exposes the status of command line flags. The attributes are read only.

New in version 2.7.3: The attribute.

¶

A structseq holding information about the float type. It contains low level information about the precision and internal representation. The values correspond to the various floating-point constants defined in the standard header file for the ‘C’ programming language; see section 5.2.4.2.2 of the 1999 ISO/IEC C standard [C99], ‘Characteristics of floating types’, for details.

attribute	float.h macro	explanation
	DBL_EPSILON	difference between 1 and the least value greater than 1 that is representable as a float
	DBL_DIG	maximum number of decimal digits that can be faithfully represented in a float; see below
	DBL_MANT_DIG	float precision: the number of base- digits in the significand of a float
	DBL_MAX	maximum representable finite float
	DBL_MAX_EXP	maximum integer e such that is a representable finite float
	DBL_MAX_10_EXP	maximum integer e such that is in the range of representable finite floats
	DBL_MIN	minimum positive normalized float
	DBL_MIN_EXP	minimum integer e such that is a normalized float
	DBL_MIN_10_EXP	minimum integer e such that is a normalized float
	FLT_RADIX	radix of exponent representation
	FLT_ROUNDS	integer constant representing the rounding mode used for arithmetic operations. This reflects the value of the system FLT_ROUNDS macro at interpreter startup time. See section 5.2.4.2.2 of the C99 standard for an explanation of the possible values and their meanings.

The attribute needs further explanation. If is any string representing a decimal number with at most significant digits, then converting to a float and back again will recover a string representing the same decimal value:

>>> importsys>>> sys.float_info.dig15>>> s='3.14159265358979'# decimal string with 15 significant digits>>> format(float(s),'.15g')# convert to float and back -> same value'3.14159265358979'

But for strings with more than significant digits, this isn’t always true:

>>> s='9876543211234567'# 16 significant digits is too many!>>> format(float(s),'.16g')# conversion changes value'9876543211234568'

¶

A string indicating how the function behaves for floats. If the string has value then for a finite float , aims to produce a short string with the property that . This is the usual behaviour in Python 2.7 and later. Otherwise, has value and behaves in the same way as it did in versions of Python prior to 2.7.

()¶

Return the interpreter’s “check interval”; see .

()¶

Return the name of the current default string encoding used by the Unicode implementation.

()¶

Return the current value of the flags that are used for calls. The flag constants are defined in the and modules. Availability: Unix.

()¶

Return the name of the encoding used to convert Unicode filenames into system file names, or if the system default encoding is used. The result value depends on the operating system:

• On Mac OS X, the encoding is .

• On Unix, the encoding is the user’s preference according to the result of nl_langinfo(CODESET), or if the failed.

• On Windows NT+, file names are Unicode natively, so no conversion is performed. still returns , as this is the encoding that applications should use when they explicitly want to convert Unicode strings to byte strings that are equivalent when used as file names.

• On Windows 9x, the encoding is .

(object)¶

Return the reference count of the object. The count returned is generally one higher than you might expect, because it includes the (temporary) reference as an argument to .

()¶

Return the current value of the recursion limit, the maximum depth of the Python interpreter stack. This limit prevents infinite recursion from causing an overflow of the C stack and crashing Python. It can be set by .

(object[, default])¶

Return the size of an object in bytes. The object can be any type of object. All built-in objects will return correct results, but this does not have to hold true for third-party extensions as it is implementation specific.

If given, default will be returned if the object does not provide means to retrieve the size. Otherwise a will be raised.

calls the object’s method and adds an additional garbage collector overhead if the object is managed by the garbage collector.

([depth])¶

Return a frame object from the call stack. If optional integer depth is given, return the frame object that many calls below the top of the stack. If that is deeper than the call stack, is raised. The default for depth is zero, returning the frame at the top of the call stack.

CPython implementation detail: This function should be used for internal and specialized purposes only. It is not guaranteed to exist in all implementations of Python.

()¶

Get the profiler function as set by .

()¶

Get the trace function as set by .

CPython implementation detail: The function is intended only for implementing debuggers, profilers, coverage tools and the like. Its behavior is part of the implementation platform, rather than part of the language definition, and thus may not be available in all Python implementations.

()¶

Return a named tuple describing the Windows version currently running. The named elements are major, minor, build, platform, service_pack, service_pack_minor, service_pack_major, suite_mask, and product_type. service_pack contains a string while all other values are integers. The components can also be accessed by name, so is equivalent to . For compatibility with prior versions, only the first 5 elements are retrievable by indexing.

platform may be one of the following values:

Constant	Platform
	Win32s on Windows 3.1
	Windows 95/98/ME
	Windows NT/2000/XP/x64
	Windows CE

product_type may be one of the following values:

Constant	Meaning
	The system is a workstation.
	The system is a domain controller.
	The system is a server, but not a domain controller.

This function wraps the Win32 function; see the Microsoft documentation on for more information about these fields.

Availability: Windows.

Changed in version 2.7: Changed to a named tuple and added service_pack_minor, service_pack_major, suite_mask, and product_type.

¶

The version number encoded as a single integer. This is guaranteed to increase with each version, including proper support for non-production releases. For example, to test that the Python interpreter is at least version 1.5.2, use:

ifsys.hexversion>=0x010502F0:# use some advanced feature...else:# use an alternative implementation or warn the user...

This is called since it only really looks meaningful when viewed as the result of passing it to the built-in function. The value may be used for a more human-friendly encoding of the same information.

The is a 32-bit number with the following layout:

Bits (big endian order)	Meaning
	(the in )
	(the in )
	(the in )
	( for alpha, for beta, for release candidate and for final)
	(the in , zero for final releases)

Thus is hexversion .

¶

A struct sequence that holds information about Python’s internal representation of integers. The attributes are read only.

Attribute	Explanation
	number of bits held in each digit. Python integers are stored internally in base
	size in bytes of the C type used to represent a digit

¶

¶

¶

These three variables are not always defined; they are set when an exception is not handled and the interpreter prints an error message and a stack traceback. Their intended use is to allow an interactive user to import a debugger module and engage in post-mortem debugging without having to re-execute the command that caused the error. (Typical use is to enter the post-mortem debugger; see chapter pdb — The Python Debugger for more information.)

The meaning of the variables is the same as that of the return values from above. (Since there is only one interactive thread, thread-safety is not a concern for these variables, unlike for etc.)

¶

The largest positive integer supported by Python’s regular integer type. This is at least 2**31-1. The largest negative integer is — the asymmetry results from the use of 2’s complement binary arithmetic.

¶

The largest positive integer supported by the platform’s Py_ssize_t type, and thus the maximum size lists, strings, dicts, and many other containers can have.

¶

An integer giving the largest supported code point for a Unicode character. The value of this depends on the configuration option that specifies whether Unicode characters are stored as UCS-2 or UCS-4.

¶

A list of finder objects that have their methods called to see if one of the objects can find the module to be imported. The method is called at least with the absolute name of the module being imported. If the module to be imported is contained in package then the parent package’s attribute is passed in as a second argument. The method returns if the module cannot be found, else returns a loader.

is searched before any implicit default finders or .

See PEP 302 for the original specification.

¶

This is a dictionary that maps module names to modules which have already been loaded. This can be manipulated to force reloading of modules and other tricks. Note that removing a module from this dictionary is not the same as calling on the corresponding module object.

¶

A list of strings that specifies the search path for modules. Initialized from the environment variable , plus an installation-dependent default.

As initialized upon program startup, the first item of this list, , is the directory containing the script that was used to invoke the Python interpreter. If the script directory is not available (e.g. if the interpreter is invoked interactively or if the script is read from standard input), is the empty string, which directs Python to search modules in the current directory first. Notice that the script directory is inserted before the entries inserted as a result of .

A program is free to modify this list for its own purposes.

Changed in version 2.3: Unicode strings are no longer ignored.

See also

Module This describes how to use .pth files to extend .

¶

A list of callables that take a path argument to try to create a finder for the path. If a finder can be created, it is to be returned by the callable, else raise .

Originally specified in PEP 302.

¶

A dictionary acting as a cache for finder objects. The keys are paths that have been passed to and the values are the finders that are found. If a path is a valid file system path but no explicit finder is found on then is stored to represent the implicit default finder should be used. If the path is not an existing path then is set.

Originally specified in PEP 302.

¶

This string contains a platform identifier that can be used to append platform-specific components to , for instance.

For most Unix systems, this is the lowercased OS name as returned by with the first part of the version as returned by appended, e.g. , at the time when Python was built. Unless you want to test for a specific system version, it is therefore recommended to use the following idiom:

ifsys.platform.startswith('freebsd'):# FreeBSD-specific code here...elifsys.platform.startswith('linux'):# Linux-specific code here...

Changed in version 2.7.3: Since lots of code check for , and there is no essential change between Linux 2.x and 3.x, is always set to , even on Linux 3.x. In Python 3.3 and later, the value will always be set to , so it is recommended to always use the idiom presented above.

For other systems, the values are:

System	value
Linux (2.x and 3.x)
Windows
Windows/Cygwin
Mac OS X
OS/2
OS/2 EMX
RiscOS
AtheOS

See also

has a coarser granularity. gives system-dependent version information.

The module provides detailed checks for the system’s identity.

¶

A string giving the site-specific directory prefix where the platform independent Python files are installed; by default, this is the string . This can be set at build time with the argument to the configure script. The main collection of Python library modules is installed in the directory while the platform independent header files (all except ) are stored in , where X.Y is the version number of Python, for example .

¶

¶

Strings specifying the primary and secondary prompt of the interpreter. These are only defined if the interpreter is in interactive mode. Their initial values in this case are and . If a non-string object is assigned to either variable, its is re-evaluated each time the interpreter prepares to read a new interactive command; this can be used to implement a dynamic prompt.

¶

Bool containing the status of the Python 3 warning flag. It’s when Python is started with the -3 option. (This should be considered read-only; setting it to a different value doesn’t have an effect on Python 3 warnings.)

(interval)¶

Set the interpreter’s “check interval”. This integer value determines how often the interpreter checks for periodic things such as thread switches and signal handlers. The default is , meaning the check is performed every 100 Python virtual instructions. Setting it to a larger value may increase performance for programs using threads. Setting it to a value 0 checks every virtual instruction, maximizing responsiveness as well as overhead.

(name)¶

Set the current default string encoding used by the Unicode implementation. If name does not match any available encoding, is raised. This function is only intended to be used by the module implementation and, where needed, by . Once used by the module, it is removed from the module’s namespace.

(n)¶

Set the flags used by the interpreter for calls, such as when the interpreter loads extension modules. Among other things, this will enable a lazy resolving of symbols when importing a module, if called as . To share symbols across extension modules, call as . Symbolic names for the flag modules can be either found in the module, or in the module. If is not available, it can be generated from using the h2py script. Availability: Unix.

(profilefunc)¶

Set the system’s profile function, which allows you to implement a Python source code profiler in Python. See chapter The Python Profilers for more information on the Python profiler. The system’s profile function is called similarly to the system’s trace function (see ), but it is called with different events, for example it isn’t called for each executed line of code (only on call and return, but the return event is reported even when an exception has been set). The function is thread-specific, but there is no way for the profiler to know about context switches between threads, so it does not make sense to use this in the presence of multiple threads. Also, its return value is not used, so it can simply return .

Profile functions should have three arguments: frame, event, and arg. frame is the current stack frame. event is a string: , , , , or . arg depends on the event type.

The events have the following meaning:

A function is called (or some other code block entered). The profile function is called; arg is .

A function (or other code block) is about to return. The profile function is called; arg is the value that will be returned, or if the event is caused by an exception being raised.

A C function is about to be called. This may be an extension function or a built-in. arg is the C function object.

A C function has returned. arg is the C function object.

A C function has raised an exception. arg is the C function object.

(limit)¶

Set the maximum depth of the Python interpreter stack to limit. This limit prevents infinite recursion from causing an overflow of the C stack and crashing Python.

The highest possible limit is platform-dependent. A user may need to set the limit higher when she has a program that requires deep recursion and a platform that supports a higher limit. This should be done with care, because a too-high limit can lead to a crash.

(tracefunc)¶

Set the system’s trace function, which allows you to implement a Python source code debugger in Python. The function is thread-specific; for a debugger to support multiple threads, it must be registered using for each thread being debugged.

Trace functions should have three arguments: frame, event, and arg. frame is the current stack frame. event is a string: , , or . arg depends on the event type.

The trace function is invoked (with event set to ) whenever a new local scope is entered; it should return a reference to a local trace function to be used that scope, or if the scope shouldn’t be traced.

The local trace function should return a reference to itself (or to another function for further tracing in that scope), or to turn off tracing in that scope.

The events have the following meaning:

A function is called (or some other code block entered). The global trace function is called; arg is ; the return value specifies the local trace function.

The interpreter is about to execute a new line of code or re-execute the condition of a loop. The local trace function is called; arg is ; the return value specifies the new local trace function. See for a detailed explanation of how this works.

A function (or other code block) is about to return. The local trace function is called; arg is the value that will be returned, or if the event is caused by an exception being raised. The trace function’s return value is ignored.

An exception has occurred. The local trace function is called; arg is a tuple ; the return value specifies the new local trace function.

Note that as an exception is propagated down the chain of callers, an event is generated at each level.

For more information on code and frame objects, refer to The standard type hierarchy.

CPython implementation detail: The function is intended only for implementing debuggers, profilers, coverage tools and the like. Its behavior is part of the implementation platform, rather than part of the language definition, and thus may not be available in all Python implementations.

(on_flag)¶

Activate dumping of VM measurements using the Pentium timestamp counter, if on_flag is true. Deactivate these dumps if on_flag is off. The function is available only if Python was compiled with . To understand the output of this dump, read in the Python sources.

CPython implementation detail: This function is intimately bound to CPython implementation details and thus not likely to be implemented elsewhere.

¶

¶

¶

File objects corresponding to the interpreter’s standard input, output and error streams. is used for all interpreter input except for scripts but including calls to and . is used for the output of and expression statements and for the prompts of and . The interpreter’s own prompts and (almost all of) its error messages go to . and needn’t be built-in file objects: any object is acceptable as long as it has a method that takes a string argument. (Changing these objects doesn’t affect the standard I/O streams of processes executed by , or the family of functions in the module.)

¶

¶

¶

These objects contain the original values of , and at the start of the program. They are used during finalization, and could be useful to print to the actual standard stream no matter if the object has been redirected.

It can also be used to restore the actual files to known working file objects in case they have been overwritten with a broken object. However, the preferred way to do this is to explicitly save the previous stream before replacing it, and restore the saved object.

¶

A triple (repo, branch, version) representing the Subversion information of the Python interpreter. repo is the name of the repository, . branch is a string of one of the forms , or . version is the output of , if the interpreter was built from a Subversion checkout; it contains the revision number (range) and possibly a trailing ‘M’ if there were local modifications. If the tree was exported (or svnversion was not available), it is the revision of

This manual documents GNU , a small and friendly text editor.

1 Introduction

GNU is a small and friendly text editor. Besides basic text editing, offers many extra features like an interactive search and replace, go to line and column number, auto-indentation, feature toggles, internationalization support, and filename tab completion.

1.1 Overview

The original goal for was a complete bug-for-bug compatible emulation of Pico, but 's current goal is to be as compatible as possible while offering a superset of Pico's functionality. See See Pico Compatibility, for more info.

The usual way to invoke is:

But it is also possible to edit several files in a row. Additionally, the cursor can be put on a desired line number by adding this number with a plus sign before any filename, and even in a desired column by adding it with a comma. So the complete synopsis is:

Email bug reports to nano@nano-editor.org.

1.2 Command Line Options

takes the following options from the command line:

Start at line number LINE and column number COLUMN (at least one of which must be specified) instead of the default of line 1, column 1.

Same as .

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.

When saving a file, back up the previous version of it to the current filename suffixed with a ~.

Set the directory where puts unique backup files if file backups are enabled.

Use bold text instead of reverse video text.

Convert typed tabs to spaces.

Enable multiple file buffers, if available.

Log search and replace strings to ~/.nano_history, so they can be retrieved in later sessions, if nanorc support is available.

Don't look at SYSCONFDIR/nanorc or ~/.nanorc, if nanorc support is available.

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.

Don't add newlines to the ends of files.

Don't convert files from DOS/Mac format.

Use the blank line below the titlebar as extra editing space.

Set the quoting string for justifying. The default value is

if extended regular expression support is available, or "> " otherwise. Note that above stands for a literal Tab character.

Restricted mode: don't read or write to any file not specified on the command line; read any nanorc files; allow suspending; allow a file to be appended to, prepended to, or saved under a different name if it already has one; or use backup files or spell checking. Also accessible by invoking with any name beginning with 'r' (e.g. "rnano").

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

Set the displayed tab length to #cols columns. The value of #cols must be greater than 0. The default value is 8.

Do quick statusbar blanking. Statusbar messages will disappear after 1 keystroke instead of 25. Note that -c overrides this.

Show the current version number and exit.

Detect word boundaries more accurately by treating punctuation characters as parts of words.

Specify a specific syntax highlighting from the nanorc to use, if available. See See Nanorc Files, for more info.

Constantly display the cursor position and line number on the statusbar. Note that this overrides -U.

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.

Show a summary of command line options and exit.

Automatically indent new lines to the same number of spaces and tabs as the previous line.

Cut from the current cursor position to the end of the current line.

When writing files, if the given file is a symbolic link, it is removed and a new file is created.

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.

Set operating directory. Makes set up something similar to a chroot.

Preserve the ^Q (XON) and ^S (XOFF) sequences so data being sent to the editor can be can be stopped and started.

Do not report errors in the nanorc file and ask them to be acknowledged by pressing Enter at startup.

Wrap lines at column #cols. If this value is 0 or less, wrapping will occur at the width of the screen less #cols, allowing it to vary along with the width of the screen if the screen is resized. The default value is -8.

Invoke the given program as the spell checker. By default, uses the command specified in the SPELL environment variable, or, if SPELL is not set, its own interactive spell checker that requires the program to be installed on your system.

Don't ask whether or not to save the current contents of the file when exiting, assume yes. This is most useful when using as the composer of a mailer program.

Enable experimental generic-purpose undo code. By default, the undo and redo shortcuts are Meta-U and Meta-E, respectively.

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.

Don't wrap long lines at any length. This option overrides any value for -r.

Expert Mode: don't show the Shortcut Lists 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.

Enable 's suspend ability using the system's suspend keystroke (usually ^Z).

Enable 'soft wrapping'. will attempt to display the entire contents of a line, even if it is longer than the screen width. Since '$' normally refers to a variable in the Unix shell, you should specify this option last when using other options (e.g. 'nano -wS$') or pass it separately (e.g. 'nano -wS -$').

Ignored, for compatibility with Pico.

2 Editor Basics

2.1 Entering Text

All key sequences in are entered using the keyboard. is a "modeless" editor. All keys, with the exception of Control and Meta key sequences, will enter text into the file being edited.

2.2 Special Functions

Special functions use the Control (Ctrl) key, displayed in the help and shortcut lists as ^; the Meta key, displayed as M; or the Escape (Esc) key.

• Control key sequences are entered by holding down the Ctrl key and pressing the desired key, or by pressing the Esc key twice and pressing the desired key.
• Pressing Esc twice and then typing a three-digit number from 000 to 255 will enter the character with the corresponding value.
• Meta key sequences are entered by holding down the Meta key (normally the Alt key) and pressing the desired key, or by pressing the Esc key once and pressing the desired key. Certain operating systems "swallow" the Alt key so that it never reaches the application; if your operating system does this, you should use the Esc key to generate Meta key sequences.

2.3 The Titlebar

The titlebar is the line displayed at the top of the editor. There are three sections: left, center and right. The section on the left displays the version of 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 will display "Modified" if the file has been modified since it was last saved or opened.

Special modes: When is in "File browser" mode, the center section will display the current directory instead of the filename. See See The File Browser, for more info.

2.4 The Statusbar

The statusbar is the third line from the bottom of the screen, or the bottom line in Expert Mode. See See Expert Mode, for more info. 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.

2.5 Shortcut Lists

The Shortcut Lists are the two lines at the bottom of the screen which show some of the more commonly used functions in the editor.

2.6 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.

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

3 Online Help

The online help system in is available by pressing ^G. It is fairly self explanatory, documenting the various parts of the editor and available keystrokes. Navigation is via the ^Y (Page Up) and ^V (Page Down) keys. ^X exits the help system.

4 Feature Toggles

Toggles allow you to change certain aspects of the editor that would normally be done via command line options. They are invoked via Meta key sequences. See See Special Functions, for more info. The following global toggles are available:

toggles the -B () command line option.

toggles the -c () command line option.

toggles the -F () command line option.

toggles the -A () command line option.

toggles the -i () command line option.

toggles the -k () command line option.

toggles the -w () command line option.

toggles the -m () command line option.

toggles the -N () command line option.

toggles the -O () command line option.

toggles whitespace display mode if you have a "whitespace" option in your nanorc. See See Nanorc Files, for more info.

toggles the -E () command line option.

toggles the -S () command line option.

toggles the -x () command line option.

toggles color syntax highlighting if you have color syntaxes in your nanorc. See See Nanorc Files, for more info.

toggles the -z () command line option.

toggles the -$ () command line option.

5 Nanorc Files

The nanorc files contain the default settings for . They should not be in DOS or Mac format. During startup, will first read its system-wide settings from SYSCONFDIR/nanorc, and then user-specific settings from ~/.nanorc.

A nanorc file accepts a series of "set" and "unset" commands, which can be used to configure on startup without using the command line options. Additionally, the "syntax", "color", and "icolor" keywords are used to define syntax highlighting rules for different text patterns. will read one command per line.

Options in nanorc files take precedence over 's defaults, and command line options override nanorc settings. Options are also unset by default, except for those that take arguments.

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 "brackets" option,

will match , , , , , and .

The supported commands and arguments are:

Use auto-indentation.

Create backup files in "filename~".

Set the directory where puts unique backup files if file backups are enabled.

Do backwards searches by default.

Use bold text instead of reverse video text.

Set the characters treated as closing brackets when justifying paragraphs. They cannot contain blank characters. Only closing punctuation, optionally followed by closing brackets, can end sentences. The default value is

Do case sensitive searches by default.

Constantly display the cursor position in the status bar.

Use cut to end of line by default, instead of cutting the whole line.

Wrap lines at column number "n". If "n" is 0 or less, the maximum line length will be the screen width less "n" columns. The default value is -8.

Enable ~/.nano_history for saving and reading search/replace strings.

Set the opening and closing brackets that can be found by bracket searches. They cannot contain blank characters. The former set must come before the latter set, and both must be in the same order. The default value is

Use the blank line below the titlebar as extra editing space.

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

Allow inserting files into their own buffers.

Don't convert files from DOS/Mac format.

Don't follow symlinks when writing files.

Don't display the help lists at the bottom of the screen.

Don't add newlines to the ends of files.

Don't wrap text at all.

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.

Preserve the XON and XOFF keys (^Q and ^S).

Set the characters treated as closing punctuation when justifying paragraphs. They cannot contain blank characters. Only closing punctuation, optionally followed by closing brackets, can end sentences. The default value is .

Do quick statusbar blanking. Statusbar messages will disappear after 1 keystroke instead of 25.

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

if you have extended regular expression support, or "> " otherwise. Note that '\\t' stands for a literal Tab character.

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.

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.

Do extended regular expression searches by default.

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.

Use smooth scrolling by default.

Use soft wrapping by default.

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

Allow to be suspended.

If is allowed to be suspended, allow the suspend key (usually ^Z) to actually suspend it.

Use a tab size of "n" columns. The value of "n" must be greater than 0. The default value is 8.

Convert typed tabs to spaces.

Save automatically on exit, don't prompt.

Enable experimental generic-purpose undo code.

Disallow file modification.

Set the two characters used to display the first characters of tabs and spaces. They must be single-column characters.

Detect word boundaries more accurately by treating punctuation characters as part of a word.

Defines a syntax named "str" which can be activated via the -Y/–syntax command line option, or will be automatically activated if the current filename matches the extended regular expression "fileregex". All following "color" and "icolor" statements will apply to "syntax" until a new syntax is defined.

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 other syntax's "fileregex".

For the currently defined syntax, display all expressions matching the extended regular expression "regex" with foreground color "fgcolor" and background color "bgcolor", at least one of which must be specified. Legal colors for foreground and background color are: white, black, red, blue, green, yellow, magenta, and cyan. You may use the prefix "bright" to force a stronger color highlight for the foreground. If your terminal supports transparency, not specifying a "bgcolor" tells "nano" to attempt to use a transparent background.

Same as above, except that the expression matching is case insensitive.

Display expressions which start with the extended regular expression "sr" and end with the extended regular expression "er" with foreground color "fgcolor" and background color "bgcolor", at least one of which must be specified. This allows syntax highlighting to span multiple lines. Note that all subsequent instances of "sr" after an initial "sr" is found will be highlighted until the first instance of "er".

Same as above, except that the expression matching is case insensitive.

Read in self-contained color syntaxes from "syntaxfile". Note that "syntaxfile" can only contain "syntax", "color", and "icolor" commands.

6 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.

7 Pico Compatibility

attempts to emulate Pico as closely as possible, but there are certain differences between the editors:

As of version 1.1.99pre1 of , text entered as search or replace strings will be stored and can be accessed with the up/down arrow keys. Previously, offered a more consistent, but incompatible with Pico, method for entering search and replace strings. In the old method, previous entries would be displayed by default as editable text in front of the cursor, as opposed to being bracketed and uneditable as it is in Pico. The old behavior could be made compatible with Pico via the option, but recent versions of Pico use the option to preserve the XON and XOFF sequences within the editor. Since, with the new method, search and replace strings can still be edited by simply hitting the up arrow key once, the old method was removed completely.

Text selected using the marking key (^^) can be written out, appended, or prepended to a new or existing file using the WriteOut key (^O).

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 of the editor on or off. Please see the internal help function (^G) for a list of what functions can be toggled for a particular version of . See See Feature Toggles, for more info.

The output of the "Display Cursor Position" in displays the given column position, as well as the row and total character position of the cursor.

It is worth noting that 's replace function is interactive, i.e. it does not stop after one search string is found and automatically replace it. The implementation will pause at each search string found and query whether to replace this instance or not. The internal spell checker operates similarly. Note that there is no way to force these functions to behave in the Pico fashion. As of version 1.1.99pre1, misspelled words are sorted and trimmed for uniqueness in the internal spell checker such that the words 'apple' and 'Apple' will be prompted for correction separately.

8 Building and Configure Options

Building from source is fairly straightforward if you are familiar with compiling programs with autoconf support:

• tar xvfz nano-x.y.z.tar.gz (where x.y.z is the version of )
• cd nano-x.y.z/
• ./configure
• make
• make install

The possible options to are:

Disable the mini file browser when reading or writing files.

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.

Disable the justify and unjustify functions.

Disable all mouse functionality. This also disables the -m command line option, which enables the mouse functionality.

Disable setting the operating directory. This also disables the -o command line option, which sets the operating directory.

Disable use of the spell checker. This also disables the -s command line option, which allows specifying an alternate spell checker.

Disable the tab completion code when reading or writing files.

Disable all long line wrapping. This also eliminates the -w command line option, which enables long line wrapping.

This option disables all the above. It also disables some of the larger internals of the editor, like the marking code and the cut to end of line code. It also disables the function toggles.

Enable support for runtime debug output. This can get pretty messy, so chances are you only want this feature to work on the nano source.

Enable extra features. At the moment, this is just easter egg-type stuff.

Enable support for syntax coloring of files using the nanorc file. This enables nanorc support as well.

Enable support for opening multiple files at a time and switching between them on the fly.

Enable support for reading the nanorc file at startup. You can store custom settings in the nanorc file rather than having to pass command line options to get desired behavior. See See Nanorc Files, for more info.

Shortcut for enabling the above four features (extra, color, multibuffer, and nanorc).

Disables Native Language support. This will disable use of the available GNU translations.

Disable long line wrapping by default when nano is run as root.

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.

Disable support for reading and writing Unicode files.

Compiling with Slang is supported, and will make the binary notably smaller than if compiled with ncurses or other curses libraries.