Xonsh Change Log



  • Fixed release.xsh to prevent it from dirtying the repo on release and leading to an unwanted .dev suffix on the version number



  • release.xsh creates a github release with the merged news entries as the release body


  • xonfig now displays the proper value for “on linux”



  • Added xclip and repo to default threadable predictors (Issues #2355 and #2348)
  • Pretty printing of the $PATH variable
  • Add “fzf-widgets” xontrib which provides fuzzy search productivity widgets with on custom keybindings to xontrib list.
  • New free_cwd xontrib for Windows, which prevent the current directory from beeing locked when the prompt is shown. This allows the other programs or Windows explorer to delete the current or parent directory. This is accomplished by reseting the CWD to the users home directory temporarily while the prompt is displayed. The directory is still locked while any commands are processed so xonsh still can’t remove it own working directory.


  • Codecov threshold to 2%


  • On Windows environments variables in wrapped like``%foo%`` are no longer expanded automatically.


  • Fixed the --rc option so it now runs xonsh with the specified rc file
  • @$ operator now functions properly when returned command is an alias
  • Correct line continuation would not work on Windows if the line continuations were used in the xonshrc file.
  • Fixed a regression in the Windows sudo command, that allows users to run elevated commands in xonsh.
  • Fix echo command from xoreutils.
  • Fixed a bug on Windows which meant xonsh wasn’t using PATH enrivonment variable but instead relying on a default value from the widnows registry.



  • Add Alt . keybinding to bashisms-xontrib to insert last argument of previous command into current buffer


  • Fix crash when openSSH version of bash is on PATH on Windows.
  • Added missing ensurers to make sure that bool env_vars are bools and int env_vars are integers:



  • The xonsh.platform.os_environ wrapper is now case-insesitive and case-preserving on Windows.
  • The private _TeeStd class will no longer attempt to write to a standard buffer after the tee has been ‘closed’ and the standard buffer returned to the system.


  • Fixed a bug on py34 where os.scandir was used by accident.
  • Line continuations (\\) is subproc mode will no longer consume the surrounding whitespace.
  • Fixed a bug if foreign_shell name was not written in lower case in the static configuration file config.json
  • Fixed a regression on Windows where caused which reported that the PATH envrionment variable could not be found.
  • Fixed issue with foregrounding jobs that were started in the background.
  • Fixed that Ctrl-C crashes xonsh after running an invalid command.
  • Fixed an potential ProcessLookupError issue, see #2288.



  • New color_tools module provides basic color tools for converting to and from various formats as well as creating pallettes from color strings.
  • Redirections may now be used in string and list-of-strings aliases.
  • Subprocess redirection may now forego the whitespace between the redirection and a file name. For example, echo hello world >/dev/null.
  • Add a -P flag to the cd function in order to change directory and following symlinks.
  • xonfig tutorial command to launch the http://xon.sh/tutorial in the browser.
  • @(...) syntax now supports generators and tuples without parentheses.
  • Sourcing foreign shells now have the --show option, which lets you see when script will be run, and the --dryrun option which prevents the source from actually taking place. Xonsh’s foreign shell API also added these keyword arguments.
  • Subprocess mode now supports subshells. Place any xonsh code between two parentheses, e.g. (cmd), to run this command in a separate xonsh subprocess.
  • Foreign shell aliases now have the ability to take extra arguments, if needed.
  • Xonsh will issue a warning message when the current working directory has been remove out from under it and not replaced prior to running the next command.
  • Line continuation backslashes are respected on Windows in the PTK shell if the backspace is is preceded by a space.
  • Added ponysay as a command which will ususally not run in a threaded mode in the commands cache.
  • New jsonutils module available for serializing special xonsh objects to JSON.


  • The literal tokens and and or must be surrounded by whitespace to delimit subprocess mode. If they do not have whitespace on both sides in subproc mode, they are condisered to be part of a command argument.
  • The xontrib command is now flagged as unthreadable and will be run on the main Python thread. This allows xontribs to set signal handlers and other operations that require the main thread.
  • nvim (Neovim) has been flagged as unthreadable
  • The interactive prompt will now catch SystemExit and, instead of exiting the session, will refresh the prompt. This is the same process as for keyboard interrupts.
  • Xonsh no longer launches the wizard for new users. Instead a welcome screen is shown which says how to launch the wizard.
  • Added Windows expanduser()-like function which prevents the expansion of ~ that are not followed by a path separator.
  • Collecting xonsh history files was reported to have random runtime OSError failures. This exception is now handled, just in case. The The exception will still be printed in debug mode.
  • Shell.stype has been renamed to Shell.shell_type.
  • The configuration wizard now displays the proper control sequence to leave the wizard at the to start of the wizard itself. Note that this is Ctrl+D for readline and Ctrl+C for prompt-toolkit.
  • Callable alias proxy functions are now more friendly to functools.partial().
  • prompt.vc.get_hg_branch now uses os.scandir to walk up the filetree looking for a .hg directory. This results in (generally) faster branch resolution compared to the subprocess call to hg root.
  • Xonsh’s script and code caches will are now invalidated whenever the xonsh version changes for a given Python version.
  • Autowrapping of subprocess globs has been improved to cover more cases that are ambiguous with Python syntax.
  • Job control info when foregrounding or backgrounding jobs will now only be displayed when xonsh is in interactive mode.
  • Enabled virtual terminal processing in the prompt-toolkit shell for Windows.


  • 3rd party pygments styles (like solorized or monokailight) are now able to be used in xonsh. These styles are dynamically created upon first use, rather than being lazily loaded by xonsh.
  • On Windows, os.environ is case insensitive. This would potentially change the case of envrionment variables set into the environment. Xonsh now uses nt.envrion, the case sensitive counterpart, to avoid these issues on Windows.
  • Fix how $PWD is managed in order to work with symlinks gracefully
  • history replay no longer barfs on style_name when setting up the environment
  • Shell.shell_type is now properly set to the same value as $SHELL_TYPE.
  • Fixed source-zsh to work with zsh v5.2.
  • Fixed issue where del (x, y) would raise a syntax error.
  • Certain vim commands issue commands involving subshells, and this is now supported.
  • Null bytes handed to Popen are now automatically escaped prior to running a subprocess. This preevents Popen from issuing embedded null byte exceptions.
  • Xonsh will no longer crash is the current working directory is removed out from under it.
  • Multiline strings can now be written in subprocess mode.
  • PTK completions will now correctly deduplicate autosuggest completions and display completions values based on the cursor position.
  • Fixed bug where trailing backspaces on Windows paths could be interpreted as line continuations characters. Now line continuation characters must be preceded by a space on Windows. This only applies to xonsh in interactive mode to ensure scripts are portable.
  • Importing *.xsh files will now respect the encoding listed in that file and properly fallback to UTF-8. This beahviour follows the rules described in PEP 263.
  • Wizard is now able to properly serialize envrionment paths.



  • New core utility function aliases (written in pure Python) are now available in xonsh.xoreutils. These include: cat, echo, pwd, tee, tty, and yes. These are not enabled by default. Use the new coreutils xontrib to load them.
  • CircleCI test post codecov run
  • The trace will automatically disable color printing when stdout is not a TTY or stdout is captured.
  • New jedi xontrib enables jedi-based tab completions when it is loaded. This supercedes xonsh’s default Python-mode completer.
  • The lexer has a new split() method which splits strings according to xonsh’s rules for whitespace and quotes.
  • New events for hooking into the Python import process are now available. You can now provide a handler for:
    • on_import_pre_find_spec
    • on_import_post_find_spec
    • on_import_pre_create_module
    • on_import_post_create_module
    • on_import_pre_exec_module
    • on_import_post_exec_module


  • The prompt toolkit shell’s first completion will now be the current token from the auto-suggetion, if available.
  • Sourcing foreign shells will now safely skip applying aliases with the same name as existing xonsh aliases by default. This prevents accitidentally overwriting important xonsh standard aliases, such as cd.


  • Threadable predicition for subprocesses will now consult both the command as it was typed in and any resolved aliases.
  • The first prompt will no longer print in the middle of the line if the user has already started typing.
  • Windows consoles will now automatically enable virtual terminal processing with the readline shell, if available. This allows the full use of ANSI escape sequences.
  • On the Windows readline shell, the teb-completion supression prompt will no longer error out depending on what you press.
  • Fixed issue with subprocess mode wrapping not repecting line continuation backslashes.
  • Handle a bug where Bash On Windows causes platform.windows_bash_command() to raise CalledProcessError.
  • Fixed issues pertaining to completing from raw string paths. This is particularly relevant to Windows, where raw strings are instered in path completion.
  • Replace deprecated calls to time.clock() by calls to time.perf_counter().
  • Use clock() to set the start time of _timings in non-windows instead of manually setting it to 0.0.
  • The trace utility will now correctly color output and not print extraneous newlines when called in a script.
  • The @$(cmd) operator now correctly splits strings according to xonsh semantics, rather than just on whitespace using str.split().
  • The mpl xontrib has been updated to improve matplotlib handling. If xontrib load mpl is run before matplotlib is imported and xonsh is in ineteractive mode, matplotlib will automatically enter interactive mode as well. Additionally, pyplot.show() is patched in interactive mode to be non-blocking. If a non-blocking show fails to draw the figre for some reason, a regular blocking version is called.
  • Fixed issues like timeit ls causing OSError - “Inappropriate ioctl for device”.
  • Fixed a potential “OSError: [Errno 22] Invalid argument” to increase job control stability.



  • New --rc command line option allows users to specify paths to run control files from the command line. This includes both xonsh-based and JSON-based configuration.
  • New $UPDATE_COMPLETIONS_ON_KEYPRESS controls whether or not completions will automatically display and update while typing. This feature is only available in the prompt-toolkit shell.


  • Xonsh scripts now report __file__ and __name__ when run as scripts or sourced. These variables have the same meaning as they do in Python scripts.
  • $XONSHRC and related configuration variables now accept JSON-based static configuration file names as elements. This unifies the two methods of run control to a single entry point and loading system.
  • The xonsh.shell.Shell() class now requires that an Execer instance be explicitly provided to its init method. This class is no longer responsible for creating an execer an its deprendencies.
  • Moved decorators unthreadable, uncapturable from xonsh.proc to xonsh.tools.
  • Some refactorings on jobs control.


  • The --config-path command line option is now deprecated in favor of --rc.


  • xonsh.environ.DEFAULT_XONSHRC has been removed due to deprecation. For this value, please check the environment instead, or call xonsh.environ.default_xonshrc(env).


  • Command pipelines that end in a callable alias are now interruptable with ^C and the processes that are piped into the alais have their file handles closed. This should ensure that the entire pipeline is closed.
  • Fixed issue where unthreadable subprocs were not allowed to be captured with the $(cmd) operator.
  • The ProcProxy class (unthreadable aliases) was not being executed and would hange if the alias was capturable. This has been fixed.
  • Fixed a tcsetattr: Interrupted system call issue when run xonsh scripts.
  • Fixed issue with ValueError being thrown from inspect.signature() when called on C-extention callables in tab completer.
  • Fixed issue that ls | less crashes on Mac.
  • Threadable prediction was incorrectly based on the user input command, rather than the version where aliases have been resolved. This has been corrected.



  • Add alias xip (“kip”) so that xonsh’s Python environment (whatever that is) can be modified.
  • HistoryEntry, a SimpleNamespace object that represents a command in history.
  • xonsh.completers.bash_completion module
  • Added option to report timing information of xonsh startup times. Start xonsh with the --timings flag to use the feature.
  • The Python tab completer will now complete the argument names of functions and other callables.
  • Uptime module added to xonsh.xoreutils. This can report the system boot time and up time.
  • The environment variable XONSH_HISTORY_BACKEND now also supports a value of class type or a History Backend instance.
  • on_envvar_new event that fires after a new envvar is created.
  • on_envvar_change event that fires after an envvar is changed.


  • history indexing api to be more simple, now returns HistoryEntry.
  • Decoupled bash_completion from xonsh project and added shim back to xonsh.
  • The JSON history backend will now unlock history files that were created prior to the last reboot.


  • Fixed broken bash completions on Windows if ‘Windows Subsystem for Linux’ is installed.
  • Readline history would try to read the first element of history prior to actually loading any history. This caused an exception to be raised on Windows at xonsh startup when using pyreadline.
  • Fixed issue with readline tab completer overwriting initial prefix in some instances.
  • Fixed issue wherein if git or (presumably) hg are aliased, then branch information no longer appears in the $PROMPT
  • Fixed an issue with commands that background themselves (such as gpg-connect-agent) not being able to be run from within xonshrc.



  • Tab completion xontrib for python applications based on click framework.
  • Added on_transform_command event for pre-processing that macros can’t handle.
  • Autodetection of backgroundability by binary analysis on POSIX.
  • New argument expand_user=True to tools.expand_path.
  • New $COMPLETION_QUERY_LIMIT environment variable for setting the number of completions above which the user will be asked if they wish to see the potential completions.
  • Users may now redirect stdout to stderr in subprocess mode.


  • The Block and Functor context managers from xonsh.contexts have been rewritten to use xonsh’s macro capabilities. You must now enter these via the with! statement, e.g. with! Block(): pass.
  • The distributed xontrib now needs to use the with! statement, since it relies on Functor.
  • telnet has been flagged as unthreadable.
  • When $DYNAMIC_CWD_ELISION_CHAR is non empty and the last dir of cwd is too long and shortened, the elision char is added at the end.
  • pygments is no longer a strict dependency of the prompt_toolkit backend. If pygments is not installed, the PTK backend will use the default ansi color settings from the terminal. Syntax highlighting requires that pygments is installed.
  • Events are now keyword arguments only
  • Restored on_precommand to its original signature.
  • Move built_ins.expand_path to tools.expand_path.
  • Rename tools.expandpath to tools._expandpath.
  • Added gvim command to unthreadable predictors.
  • The source alias now passes $ARGS down to file it is sourcing.


  • XonshBlockError has been removed, since it no longer serves a purpose.


  • PopenThread will now re-issue SIGINT to the main thread when it is recieved.
  • Fixed an issue that using sqlite history backend does not kill unfinished jobs when quitting xonsh with a second “exit”.
  • Fixed an issue that xonsh would fail over to external shells when running .xsh script which raises exceptions.
  • Fixed an issue with openpty() returning non-unix line endings in its buffer. This was causing git and ssh to fail when xonsh was used as the login shell on the server. See https://mail.python.org/pipermail/python-list/2013-June/650460.html for more details.
  • Restored the ability to ^Z and fg processes on posix platforms.
  • CommandPipelines were not gauranteeded to have been ended when the return code was requested. This has been fixed.
  • Introduce path expansion in is_writable_file to fix $XONSH_TRACEBACK_LOGFILE=~/xonsh.log.
  • Backgrounding a running process (^Z) now restores ECHO mode to the terminal in cases where the subprocess doesn’t properly restore itself. A major instance of this behaviour is Python’s interactive interpreter.
  • Readline backend would not ask the user to confirm the printing of completion options if they numbered above a certain value. Instead they would be dumped to the screen. This has been fixed.
  • Jupyter kernel was no longer properly running subprocess commands. This has been fixed.
  • The filename is applied to the target of the source alias, providing better tracebacks.



  • Added weechat to default predictors
  • $DYNAMIC_CWD_ELISION_CHAR environment variable to control how a shortened path is displayed.


  • _ret_code function of prompt_ret_code xontrib return now None when return code is 0 instead of empty string allowing more customization of prompt format.


  • Minor Python completer token counting bug fix.
  • multiline syntax error in PTK shell due to buffer not being reset
  • Segfaults and other early exit signals are now reported correctly, again.
  • tests/bin/{cat,pwd,wc} shebang changed to python3



  • Fixed xonfig raising error when xonsh is not installed from source.



  • $XONTRIB_MPL_MINIMAL environment variable can be set to change if plots are minimalist or as-seen
  • xontrib-mpl now supports iTerm2 inline image display if iterm2_tools python package is installed
  • Xonsh now will fallback to other shells if encountered errors when starting up.
  • Added entry to customization faq re: dirs alias (#1452)
  • Added entry to customization faq re: tab completion selection (#1725)
  • Added entry to customization faq re: libgcc core dump (#1160)
  • Section about quoting in the tutorial.
  • The $VC_HG_SHOW_BRANCH environement variable to control whether to hide the hg branch in the prompt.
  • xonfig now contains the latest git commit date if xonsh installed from source.
  • Alt+Enter will execute a multiline code block irrespective of cursor position
  • Windows now has the ability to read output asyncronously from the console.
  • Use doctr to deploy dev docs to github pages
  • New xonsh.proc.uncapturable() decorator for declaring that function aliases should not be run in a captured subprocess.
  • New history backend sqlite.
  • Prompt user to install xontrib package if they try to load an uninstalled xontrib
  • Callable aliases may now take a final spec arguemnt, which is the cooresponding SubprocSpec instance.
  • New bashisms xontrib provides additional Bash-like syntax, such as !!. This xontrib only affects the command line, and not xonsh scripts.
  • Tests that create testing repos (git, hg)
  • New subprocess specification class SubprocSpec is used for specifiying and manipulating subprocess classes prior to execution.
  • New PopenThread class runs subprocesses on a a separate thread.
  • New CommandPipeline and HiddenCommandPipeline classes manage the execution of a pipeline of commands via the execution of the last command in the pipeline. Instances may be iterated and stream lines from the stdout buffer. These pipelines read from the stdout & stderr streams in a non-blocking manner.
  • $XONSH_STORE_STDOUT is now available on all platforms!
  • The CommandsCache now has the ability to predict whether or not a command must be run in the foreground using Popen or may use a background thread and can use PopenThread.
  • Callable aliases may now use the full gamut of functions signatures: f(), f(args), f(args, stdin=None), f(args, stdin=None, stdout=None), and ` f(args, stdin=None, stdout=None, stderr=None).
  • Uncaptured subprocesses now recieve a PTY file handle for stdout and stderr.
  • New $XONSH_PROC_FREQUENCY environment variable that specifies how long loops in the subprocess framwork should sleep. This may be adjusted from its default value to improved perfromance and mitigate “leaky” pipes on slower machines.
  • Shift+Tab moves backwards in completion dropdown in prompt_toolkit
  • PromptFormatter class that holds all the related prompt methods
  • PromptFormatter caching when building the prompt
  • p-strings: p'/foo/bar' is short for pathlib.Path('/foo/bar')
  • byte strings: prefixes other than b'foo' (eg, RB'foo') now work
  • Backticks for regex or glob searches now support an additional modifier p, which causes them to return Path objects instead of strings.
  • New BOTTOM_TOOLBAR environment variable to control a bottom toolbar as specified in prompt-toolkit
  • New $XONSH_STDERR_PREFIX and $XONSH_STDERR_POSTFIX environment variables allow the user to print a prompt-like string before and after all stderr that is seen. For example, say that you would like stderr to appear on a red background, you might set $XONSH_STDERR_PREFIX = "{BACKGROUND_RED}" and $XONSH_STDERR_PREFIX = "{NO_COLOR}".
  • New xonsh.pyghooks.XonshTerminal256Formatter class patches the pygments formatter to understand xonsh color token semantics.
  • Load events are now available
  • New events added: on_post_init, on_pre_cmdloop, on_pre_rc, on_post_rc, on_ptk_create
  • Completion for xonsh builtin functions xontrib and xonfig
  • Added a general customization FAQ page to the docs to collect various tips/tricks/fixes for common issues/requests
  • test_single_command and test_redirect_out_to_file tests in test_integrations
  • Add note that the target of redirection should be separated by a space.


  • CircleCI now handles flake8 checks

  • Travis doesn’t allow failures on nightly

  • get_hg_branch runs hg root to find root dir and check if we’re in repo

  • The default style will now use the color keywords (#ansired, #ansidarkred) to set colors that follow the terminal color schemes. Currently, this requires prompt_toolkit master (>1.0.8) and pygments master (2.2) to work correctly.

  • vox activate now accepts relative directories.

  • Updated the effectivity of $XONSH_DEBUG on debug messages.

  • Better documentation on how to get nice colors in Windows’ default console

  • All custom prompt_toolkit key binding filters now declared with the @Condition decorator

  • The style for the prompt toolkit completion menu is now lightgray/darkgray instead of turquoise/teal

  • landscape.io linting now ignores ply directory

  • history help messages to reflect subcommand usage

  • Quote all paths when completion if any of the paths needs be quoted, so that bash can automatically complete to the max prefix of the paths.

  • Tee’d reads now occur in 1kb chunks, rather than character-by-character.

  • The which alias no longer has a trailing newline if it is captured. This means that $(which cmd) will simply be the path to the command.

  • The following commands are, by default, predicted to be not threadable in some circumstances:

    • bash
    • csh
    • clear
    • clear.exe
    • cls
    • cmd
    • ex
    • fish
    • htop
    • ksh
    • less
    • man
    • more
    • mutt
    • nano
    • psql
    • ranger
    • rview
    • rvim
    • scp
    • sh
    • ssh
    • startx
    • sudo
    • tcsh
    • top
    • vi
    • view
    • vim
    • vimpager
    • xo
    • xonsh
    • zsh
  • The run_subproc() function has been replaced with a new implementation.

  • Piping between processes now uses OS pipes.

  • $XONSH_STORE_STDIN now uses os.pread() rather than tee and a new file.

  • The implementation of the foreground() decorator has been moved to unthreadable().

  • voxapi.Vox now supports pathlib.Path and PathLike objects as virtual environment identifiers


  • BaseShell instantiates PromptFormatter

  • readline/ptk shells use PromptFormatter

  • Updated the bundled version of ply to current master available

  • vended ply is now a git subtree to help with any future updates

  • WHITE color keyword now means lightgray and INTENSE_WHITE commpletely white

  • Removed add_to_shell doc section from *nix install pages and instead relocated it to the general customization page

  • Moved a few *nix customization tips from the linux install page to the general customization page


  • coverage checks
  • CompletedCommand and HiddenCompletedCommand classes have been removed in favor of CommandPipeline and HiddenCommandPipeline.
  • SimpleProcProxy and SimpleForegroundProcProxy have been removed in favor of a more general mechanism for dispatching callable aliases implemented in the ProcProxyThread and ProcProxy classes.
  • test_run_subproc.py in favor of test_integrations.py
  • Unused imports in many tests
  • Many duplicated tests (copypasta)


  • xontrib-mpl now preserves the figure and does not permanently alter it for viewing
  • Fix up small pep8 violations
  • Fixed a bug where some files are not showing using bash completer
  • Fixed some issues with subprocess capturing aliases that it probably shouldn’t.
  • safe_readable() now checks for ValueError as well.
  • The scroll bars in the PTK completions menus are back.
  • Jupyter kernel installation now respects the setuptools root parameter.
  • Fix __repr__ and __str__ methods of SubprocSpec so they report correctly
  • Fixed the meassage printed when which is unable to find the command.
  • Fixed a handful of sphinx errors and warnings in the docs
  • Fixed many PEP8 violations that had gone unnoticed
  • Fix failure to detect an Anaconda python distribution if the python was install from the conda-forge channel.
  • current_branch will try and locate the vc binary once
  • May now Crtl-C out of an infinite loop with a subprocess, such as `while True: sleep 1.
  • Fix for stdin redirects.
  • Backgrounding works with $XONSH_STORE_STDOUT
  • PopenThread blocks its thread from finishing until command has completed or process is suspended.
  • Added a minimum time buffer time for command pipelines to check for if previous commands have executed successfully. This is helpful for pipelines where the last command takes a long time to start up, such as GNU Parallel. This also checks to make sure that output has occured. This includes piping 2+ commands together and pipelines that end in unthreadable commands.
  • curr_branch reports correctly when git config status.short true is used
  • pip completion now filters results by prefix
  • Fixed streaming !(alias) repr evaluation where bytes where not streamed.
  • Aliases that begin with a comma now complete correctly (no spurious comma)
  • Use python3 in shebang lines for compatibility with distros that still use Python 2 as the default Python
  • STDOUT is only stored when $XONSH_STORE_STDOUT=True
  • Fixed issue with alais redirections to files throwing an OSError because the function ProcProxies were not being waited upon.
  • Fixed issue with callablable aliases that happen to call sys.exit() or raise SystemExit taking out the whole xonsh process.
  • Safely flushes file handles on threaded buffers.
  • Proper default value and documentation for $BASH_COMPLETIONS
  • Fixed readline completer issues on paths with spaces
  • Fix bug in argvquote() functions used when sourcing batch files on Windows. The bug meant an extra backslash was added to UNC paths. Thanks to @bytesemantics for spotting it, and @janschulz for fixing the issue.
  • pep8, lint and refator in pytest style of test_ptk_multiline.py, test_replay.py
  • Tab completion of aliases returned a upper cased alias on Windows.
  • History show all action now also include current session items.
  • proc.stream_stderr now handles stderr that doesn’t have buffer attribute
  • Made history show result sorted.
  • Fixed issue that history gc does not delete empty history files.
  • Standard stream tees have been fixed to accept the possibility that they may not be backed by a binary buffer. This inludes the pipeline stdout tee as well as the shell tees.
  • Fixed a bug when the pygments plugin was used by third party editors etc.
  • CPU usage of PopenThread and CommandPipeline has been brought down significantly.



  • Define alias for ‘echo’ on startup for Windows only.
  • New coredev astronouth7303 added
  • which -a now searches in __xonsh_ctx__ too
  • Info about the xontrib cookiecutter template on xontrib tutorial
  • xonsh’s optional dependencies may now be installed with the pip extras ptk, proctitle, linux, mac, and win.
  • Env help method to format and print the vardocs for an envvar
  • test_news fails if no empty line before a category
  • more info on test_news failures
  • Added on_precommand and on_postcommand events
  • New FORMATTER_DICT entry gitstatus to provides informative git status
  • FOREIGN_ALIASES_OVERRIDE envvar to control whether foreign aliases should override xonsh aliases with the same name.
  • Warning on tutorial about foreign aliases being ignored if a xonsh alias exist with the same name if not FOREIGN_ALIASES_OVERRIDE.
  • The prompt-toolkit shell now auto-inserts matching parentheses, brackets, and quotes. Enabled via the XONSH_AUTOPAIR environment variable
  • Better syntax highlights in prompt-toolkit, including valid command / path highlighting, macro syntax highlighting, and more
  • More info on tutorial about history interaction
  • Entry on bash_to_xsh
  • Macro context managers are now available via the with! syntax.


  • Devguide reflects the current process of releasing through release.xsh
  • moved which from xonsh.aliases into xoreutils.which
  • xonsh.prompt.gitstatus.gitstatus now returns a namedtuple
  • implementation of xonsh.prompt.vc_branch.get_git_branch and xonsh.prompt.vc_branch.git_dirty_working_directory to use ‘git status –procelain’
  • moved prompt formatting specific functions from xonsh.environ to xonsh.prompt.base
  • All prompt formatter functions moved to xonsh.prompt subpackage
  • Printing the message about foreign aliases being ingored happens only if XONSH_DEBUG is set.
  • Use SetConsoleTitleW() on Windows instead of a process call.
  • Tutorial to reflect the current history command argument functionality
  • Macro function arguments now default to str, rather than eval, for consistentcy with other parts of the macro system.


  • aliases that use ‘!’ in their name cause they clash with the macro syntax


  • Fix regression where bash git completions where not loaded automatically when GitForWindows is installed.

  • More tokens are now supported in subproc args, such as ==.

  • Python completions now work without space delimiters, e.g. a=matpl<TAB> will complete to a=matplotlib

  • Parser would fail on nested, captured suprocess macros. Now, it works, hooray!?

  • now fires chdir event if OS change in working directory is detected.

  • xonsh.prompt.vc_branch.git_dirty_working_directory

    uses porcelain option instead of using the bytestring nothing to commit to find out if a git directory is dirty

  • Fix bug where know commands where not highlighed on windows.

  • Fixed completer showing executable in upper case on windows.

  • Fixed issue where tilde expansion was occuring more than once before an equals sign.

  • test_dirstack test_cdpath_expansion leaving stray testing dirs

  • Better completer display for long completions in prompt-toolkit

  • Automatucally append newine to target of source alias, so that it may be exec’d.

  • test_news fails when single graves around word

  • Slashes in virtual environment names work in vox

  • non string type value in $FORMATTER_DICT turning prompt ugly

  • whole prompt turning useless when one formatting function raises an exception

  • Fix completion after alias expansion

  • Fix hard crash when foreign shell functions fails to run. #1715

  • Bug where non-default locations for XDG_DATA_HOME and XONSH_DATA_DIR would not expand ~ into the home directory

  • Auto quote path completions if path contains ‘and’ or ‘or’

  • Completion now works on subcommands after pipe, &&, || and so on.

  • cd . and cd <singleCharacter> now work. Fix indexerror in AUTO_PUSHD case, too.

  • Fixed issue with accidentally wrapping generators inside of function calls.

  • History indexing with string returns most recent command.



  • New option COMPLETIONS_CONFIRM. When set, <Enter> is used to confirm completion instead of running command while completion menu is displayed.
  • NetBSD is now supported.
  • Macro function calls are now available. These use a Rust-like f!(arg) syntax.
  • Macro subprocess call now avalaible with the echo! x y z syntax.
  • A new event subsystem has been added.
  • howto install sections for Debian/Ubuntu and Fedora.
  • History methods __iter__ and __getitem__
  • tools.get_portions that yields parts of an iterable
  • Added a py.test plugin to collect test_*.xsh files and run test_*() functions.
  • __repr__ and __str__ magic method on LazyObject


  • create_module implementation on XonshImportHook
  • Results of the bash tab completer are now properly escaped (quoted) when necessary.
  • Foreign aliases that match xonsh builtin aliases are now ignored with a warning.
  • prompt_toolkit completions now only show the rightmost portion of a given completion in the dropdown
  • The value of 'none' is no longer allowed for $SHELL_TYPE just during the initial load from the environment. -D, later times, and other sources still work.
  • yacc_debug=True now load the parser on the same thread that the Parser instance is created. setup.py now uses this synchronous form as it was causing the parser table to be missed by some package managers.
  • Tilde expansion for the home directory now has the same semantics as Bash. Previously it only matched leading tildes.
  • Context sensitive AST transformation now checks that all names in an expression are in scope. If they are, then Python mode is retained. However, if even one is missing, subprocess wrapping is attempted. Previously, only the left-most name was examined for being within scope.
  • dirstack.pushd and dirstack.popd now handle UNC paths (of form \\<server>\<share>\...), but only on Windows. They emulate behavior of CMD.EXE by creating a temporary mapped drive letter (starting from z: down) to replace the \\<server>\<share> portion of the path, on the pushd and unmapping the drive letter when all references to it are popped.
  • And dirstack suppresses this temporary drive mapping funky jive if registry entry HKCU\software\microsoft\command processor\DisableUNCCheck (or HKLM...) is a DWORD value 1. This allows Xonsh to show the actual UNC path in your prompt string and also allows subprocess commands invoking CMD.EXE to run in the expected working directory. See https://support.microsoft.com/en-us/kb/156276 to satisfy any lingering curiosity.
  • lazy_locate_binary handles binary on different drive letter than current working directory (on Windows).
  • _curr_session_parser now iterates over History
  • New implementation of bash completer with better performance and compatibility.
  • $COMPLETIONS_BRACKETS is now available to determine whether or not to include opening brackets in Python completions
  • xonsh.bat tries to use pylauncher when available.


  • History method show
  • _hist_get_portion in favor of tools.get_portions
  • Unused imports in proc, flake8.


  • xonsh modules imported now have the __file__ attribute
  • Context senstitive AST transformer was not adding argument names to the local scope. This would then enable extraneous subprocess mode wrapping for expressions whose leftmost name was function argument. This has been fixed by properly adding the argument names to the scope.
  • Foreign shell functions that are mapped to empty filenames no longer receive alaises since they can’t be found to source later.
  • Correctly preserve arguments given to xon.sh, in case there are quoted ones.
  • Environment variables in subprocess mode were not being expanded unless they were in a sting. They are now expanded properly.
  • Fixed a bug that prevented xonsh from running scripts with code caching disabled.
  • Text of instructions to download missing program now does not get off and appears in whole.
  • Fix some test problems when win_unicode_console was installed on windows.
  • Fixed bug that prompt string and $PWD failed to track change in actual working directory if the invoked Python function happened to change it (e.g via `os.chdir()`. Fix is to update $PWD after each command in `BaseShell.default()`.
  • The interactive prompt now correctly handles multiline strings.
  • cd \\<server>\<share> now works when $AUTO_PUSHD is set, either creating a temporary mapped drive or simply setting UNC working directory based on registry DisableUNCCheck. However, if $AUTO_PUSHD is not set and UNC checking is enabled (default for Windows), it issues an error message and fails. This improves on prior behavior, which would fail to change the current working directory, but would set $PWD and prompt string to the UNC path, creating false expectations.
  • fix parsing for tuple of tuples (like (),())
  • sys.stdin, sys.stdout, sys.stderr no longer complete with opening square brackets
  • xonsh now properly handles syntax error messages arising from using values in inappropriate contexts (e.g., del 7).



  • _hist_get that uses generators to filter and fetch the history commands of each session.

  • -n option to the show subcommand to choose to numerate the commands.

  • The exec command is now a first class alias that acts the same way as in sh-based languages. It replaces the current process with the command and argument that follows it. This allows xonsh to be used as a default shell while maintaining functionality with SSH, gdb, and other third party programs that assume the default shell supports raw exec command [args] syntax.

    This feature introduces some ambiguity between exec-as-a-subprocess and exec-as-a-function (the inescapable Python builtin). Though the two pieces of syntax do not overlap, they perform very different operations. Please see the xonsh FAQ for more information on trade-offs and mitigation strategies.

  • which -v now calls superhelp, which will print highlighted source.

  • Added xontribs: * z (Tracks your most used directories, based on ‘frecency’.)

  • amalgamate.py now supports relative imports.

  • history show args -t, -f, -T +T to filter commands by timestamp

  • ensure_timestamp in xonsh.tools to try and convert an object to a timestamp a.k.a float

  • $XONSH_DATETIME_FORMAT envvar, the default format to be used with datetime.datetime.strptime()

  • xon.sh script now sets $LANG=C.UTF8 in the event that no encoding is detected.

  • amalgamate.py now properly handles from __future__ imports.


  • _hist_show now uses _hist_get to print out the commands.

  • xonsh.completers sub-package is now fully lazy.

  • The vox xontrib now takes flags very similar to Python’s venv tool. Use vox --help <command> to learn more.

  • Xontribs may now define __all__ as a module top-level to limit what gets exported to the shell context

  • xon.sh uses the interpreter used to install instead of the default python3.

  • imphooks now checks directory access rights.

  • $TITLE now changes both icon (tab) and window title

  • Moved amalgamate_source outside build_tables

  • Disable amalgamation on setup develop

  • _hist_parse_args implementation refactor

  • moved all parameter checking in _hist_get

  • _hist_show to handle numeration and timestamp printing of commands

  • xonsh.imphooks does not install the import hooks automatically, you now need to explicitly call the install_hook() method defined in this module. For example: from xonsh.imphooks import install_hook; install_hook(). The install_hook method can safely be called several times. If you need compatibility with previous versions of Xonsh you can use the following:

    from xonsh import imphooks
    getattr(imphooks, 'install_hook', lambda:None)()
  • xonfig command now dumps more encoding related settings.


  • Anaconda Build is shutting down so we can no longer build conda development packages. All references to these packages are removed from the documentation.
  • Removed conda build recipe since the it is no longer used for Anaconda Build. The recipe used to build xonsh on conda-forge can be found here: https://github.com/conda-forge/xonsh-feedstock/blob/master/recipe/meta.yaml


  • _zsh_hist_parser not parsing history files without timestamps.
  • Fixed amalgamation of aliased imports that are already in sys.modules.
  • Xonsh will no longer fail to start in directories where the user doesn’t have read access.
  • Fixed parser error line number exception from being raised while trying to raise a SyntaxError.
  • Made pip completer more robust to when pip is not installed.
  • Fix a startup problem on windows caused by a refactor of Prompt_toolkit. https://github.com/jonathanslenders/python-prompt-toolkit/commit/a9df2a2
  • ensure_slice bugfix for -1 index/slice
  • Alias tab completion works again
  • Version number reported by bundled PLY
  • xonfig no longer breaks if PLY is externally installed and version 3.8
  • LazyObject supports set union
  • Fixed error with not sourcing files with $XONSH_ENCODING and $XONSH_ENCODING_ERRORS.
  • $IGNOREEOF envrionment variable now works properly in the prompt-toolkit shell.
  • Completions in jupyter_kernel.py now use updated completion framework



  • New lazyobject(), lazydict(), and lazybool() decorators to turn functions into lazy, global objects.

  • vox remove command can remove multiple environments at once.

  • Added FreeBSD support.

  • Tab completion for pip python package manager.

  • Regular expressions for enviroment variable matching

  • __contains__ method on Env

  • Added news tests to enforce changelog conformity.

  • A new way to add optional items to the prompt format string has been added. Instead of relying on formatter dict items being padded with a space, now the padding characters are specified in the format string itself, in place of the format spec (after a :).

    For example, previously the prompt string {cwd}{curr_branch} $ would rely on curr_branch giving its output prepended with a space for separation, or outputting nothing if it is not applicable. Now curr_branch just outputs a value or None, and the prompt string has to specify the surrounding characters: {cwd}{curr_branch: {}} $. Here the value of curr_branch will be prepended with a space ({} is a placeholder for the value itself). The format string after : is applied only if the value is not None.

  • xonsh.completers subpackage is now amalgamated.

  • amalgamate.py will now warn if the same name is defined across multiple different files.

  • xonsh_builtins, xonsh_execer fixtures in conftest.py

  • Docs on how to tweak the Windows ConHost for a better color scheme.

  • Docs: how to fix Thunar’s “Open Terminal Here” action.

  • A new API class was added to Vox: xontrib.voxapi.Vox. This allows programtic access to the virtual environment machinery for other xontribs. See the API documentation for details.

  • History now accepts multiple slices arguments separated by spaces


  • amalgamate now works on Python 2 and allows relative imports.
  • Top-level xonsh package now more lazy.
  • Show conda environement name in prompt in parentheses similiar what conda does.
  • Implementation of expandvars now uses regex
  • Because of the addition of “optional items” to the prompt format string, the functions xonsh.environ.current_branch, xonsh.environ.env_name and formatter dict items curr_branch, current_job, env_name are no longer padded with a separator.
  • many test cases to use fixtures and parametrization
  • Public interface in xonsh.ansi_colors module now has ansi_ prefix to prevent name conflicts with other parts of xonsh.
  • Vox was moved to xontrib. Behaves exactly the same as before, just need to add it to your xontribs.
  • is_int_as_str and is_slice_as_str are now reimplemented in EAFP style


  • yield statements (nose style) and for loops in tests
  • is_int_or_slice


  • _is_in_env, _get_env_string functions on tools
  • xonsh.environ.format_prompt has been dropped; partial_format_prompt can be used instead.
  • for loops and yield statements in test cases, unused imports
  • is_int_or_slice


  • Fixed bug on Windows preventing xonsh from changing the console title.
  • Unrecognized $XONSH_COLOR_STYLE values don’t crash terminal.
  • Writing the window title will no longer accidentally answer interactive questions, eg rm -i now works as expected.
  • more matching cases for envvar reference
  • Certain linux VTE terminals would not start new tabs in the previous CWD. This may now be rectified by adding {vte_new_tab_cwd} somewhere to the prompt.
  • Unqualified usage of Unstorable in xonsh setup wizard that was causing the wizard to crash and burn
  • Bare except: was replaced with except Exception to prevent accidentally catching utility exceptions such as KeyboardInterrupt, which caused unexpected problems like printing out the raw $PROMPT string.
  • Fixed multiple definition of EQUAL.
  • Fixed multiple definition of pprint.
  • Fixed multiple definition of pyghooks.
  • Fixed multiple definition of pygments.
  • Fixed multiple definition of tokenize.
  • redundant and ‘leaky’ tests in nose
  • Fix bug that prevented disabling $INTENSIFY_COLORS_ON_WIN in xonshrc
  • LazyJSON will now hide failures to close, and instead rely on reference counting if something goes wrong.
  • Fixed maximum recurssion error with color styles.
  • Parser tables will no longer be generated in the current directory by accident.
  • Error messages when zsh or bash history file is not found



  • The results of glob expressions are sorted if $GLOB_SORTED is set.
  • LazyObjects will now load themselves on __getitem__()
  • New tools in xonsh.lazyasd module for loading modules in background threads.


  • GLOB_SORTED is enabled by default.
  • Sped up loading of pygments by ~100x by loading pkg_resources in background.
  • Sped up loading of prompt-toolkit by ~2x-3x by loading pkg_resources in background.
  • setup.py will no longer git checkout to replace the version number. Now it simply stores and reuses the original version line.


  • Removed the xonsh.built_ins.ENV global instance of the Env class.


  • Bug with setting hist size not being settable due to lazy object loading has been resolved.
  • Minor amalgamate bug with import pkg.mod amalgamated imports.
  • No longer raises an error if a directory in $PATH does not exist on Python v3.4.
  • Fixed a readline shell completion issue that caused by inconsistence between $CASE_SENSITIVE_COMPLETIONS and readline’s inputrc setting.



  • dev versions now display a devN counter at the end and xonfig info also displays the git sha of the current build


  • prompt_toolkit completion no longer automatically selects the first entry on first tab-press when completing multiple directories at once


  • Sourcing foreign shells now allow fully capture environment variables that contain newlines as long as they also don’t contain equal signs.
  • Added scripts directory to MANIFEST.in



  • setup.py will only amalgamate source files if amalgamate.py is available. This fixes issues with installing from pip.



  • A new class, xonsh.tools.EnvPath has been added. This class implements a MutableSequence object and overrides the __getitem__ method so that when its entries are requested (either explicitly or implicitly), variable and user expansion is performed, and relative paths are resolved. EnvPath accepts objects (or lists of objects) of str, bytes or pathlib.Path types.

  • New amalgamate tool collapses modules inside of a package into a single __amalgam__.py module. This tool glues together all of the code from the modules in a package, finds and removes intra-package imports, makes all non-package imports lazy, and adds hooks into the __init__.py. This helps makes initial imports of modules fast and decreases startup time. Packages and sub-packages must be amalgamated separately.

  • New lazy and self-destructive module xonsh.lazyasd adds a suite of classes for delayed creation of objects.

    • A LazyObject won’t be created until it has an attribute accessed.
    • A LazyDict will load each value only when a key is accessed.
    • A LazyBool will only be created when __bool__() is called.

    Additionally, when fully loaded, the above objects will replace themselves by name in the context that they were handed, thus derefenceing themselves. This is useful for global variables that may be expensive to create, should only be created once, and may not be used in any particular session.

  • New xon.sh script added for launching xonsh from a sh environment. This should be used if the normal xonsh script does not work for some reason.

  • Normal globbing is now available in Python mode via g``

  • Backticks were expanded to allow searching using arbitrary functions, via @<func>``

  • xonsh.platform now has a new PATH_DEFAULT variable.

  • Tab completers can now raise StopIteration to prevent consideration of remaining completers.

  • Added tab completer for the completer alias.

  • New Block and Functor context managers are now available as part of the xonsh.contexts module.

  • Block provides support for turning a context body into a non-executing list of string lines. This is implmement via a syntax tree transformation. This is useful for creating remote execution tools that seek to prevent local execution.

  • Functor is a subclass of the Block context manager that turns the block into a callable object. The function object is available via the func() attribute. However, the Functor instance is itself callable and will dispatch to func().

  • New $VC_BRANCH_TIMEOUT environment variable is the time (in seconds) of how long to spend attempting each individual version control branch information command during $PROMPT formatting. This allows for faster prompt resolution and faster startup times.

  • New lazy methods added to CommandsCache allowing for testing and inspection without the possibility of recomputing the cache.

  • !(command) is now usefully iterable, yielding lines of stdout

  • Added XonshCalledProcessError, which includes the relevant CompletedCommand. Also handles differences between Py3.4 and 3.5 in CalledProcessError

  • Tab completion of paths now includes zsh-style path expansion (subsequence matching), toggleable with $SUBSEQUENCE_PATH_COMPLETION

  • Tab completion of paths now includes “fuzzy” matches that are accurate to within a few characters, toggleable with $FUZZY_PATH_COMPLETION

  • Provide $XONSH_SOURCE for scripts in the environment variables pointing to the currently running script’s path

  • Arguments ‘+’ and ‘-‘ for the fg command (job control)

  • Provide $XONSH_SOURCE for scripts in the environment variables pointing to the currently running script’s path

  • !(command) is now usefully iterable, yielding lines of stdout

  • Added XonshCalledProcessError, which includes the relevant CompletedCommand. Also handles differences between Py3.4 and 3.5 in CalledProcessError

  • XonshError and XonshCalledProcessError are now in builtins:

    • history session
    • history xonsh
    • history all
    • history zsh
    • history bash
    • __xonsh_history__.show()
  • New pathsep_to_set() and set_to_pathsep() functions convert to/from os.pathsep separated strings to a set of strings.


  • Changed testing framework from nose to pytest
  • All PATH-like environment variables are now stored in an EnvPath object, so that non-absolute paths or paths containing environment variables can be resolved properly.
  • In VI_MODE, the v key will enter character selection mode, not open the editor. Ctrl-X Ctrl-E will still open an editor in any mode
  • $XONSH_DEBUG will now supress amalgamted imports. This usually needs to be set in the calling environment or prior to any xonsh imports.
  • Restuctured xonsh.platform to be fully lazy.
  • Restuctured xonsh.ansi_colors to be fully lazy.
  • Ensured the pygments and xonsh.pyghooks are not imported until actually needed.
  • Yacc parser is now loaded in a background thread.
  • Cleaned up argument parsing in xonsh.main.premain by removing the undo_args hack.
  • Now complains on invalid arguments.
  • Env now guarantees that the $PATH is available and mutable when initialized.
  • On Windows the PROMPT environment variable is reset to $P$G before sourcing *.bat files.
  • On Windows the PROMPT environment variable is reset to $P$G before starting subprocesses. This prevents the unformatted xonsh PROMPT tempalte from showing up when running batch files with ECHO ON`
  • @() now passes through functions as well as strings, which allows for the use of anonymous aliases and aliases not explicitly added to the aliases mapping.
  • Functions in Execer now take transform kwarg instead of wrap_subproc.
  • Provide $XONSH_SOURCE for scripts in the environment variables pointing to the currently running script’s path
  • XonshError and XonshCalledProcessError are now in builtins
  • __repr__ on the environment only shows a short representation of the object instead of printing the whole environment dictionary
  • More informative prompt when configuring foreign shells in the wizard.
  • CommandsCache is now a mapping from command names to a tuple of (executable locations, has alias flags). This enables faster lookup times.
  • locate_bin() now uses the CommandsCache, rather than scanning the $PATH itself.
  • $PATHEXT is now a set, rather than a list.
  • Ignore case and leading a quotes when sorting completions


  • The 'console_scripts' option to setuptools has been removed. It was found to cause slowdowns of over 150 ms on every startup.
  • Bash is no longer loaded by default as a foreign shell for initial configuration. This was done to increase stock startup times. This behaviour can be recovered by adding {"shell": "bash"} to your "foreign_shells" in your config.json file. For more details, see http://xon.sh/xonshconfig.html#foreign-shells
  • ensure_git() and ensure_hg() decorators removed.
  • call_hg_command() function removed.


  • Issue where xonsh did not expand user and environment variables in $PATH, forcing the user to add absolute paths.
  • Fixed a problem with aliases not always beeing found.
  • Fixed issue where input was directed to the last process in a pipeline, rather than the first.
  • Bug where xonfig wizard can’t find ENV docs
  • Fixed xonsh.environ.locate_binary() to handle PATH variable are given as a tuple.
  • Fixed missing completions for cd and `rmdir when directories had spaces in their names.
  • Bug preventing xonsh executable being installed on macOS.
  • Strip leading space in commands passed using the “-c” switch
  • Fixed xonfig wizard failing on Windows due to colon in created filename.
  • Ensured that the prompt_toolkit shell functions, even without a completer attribute.
  • Fixed crash resulting from malformed $PROMPT or $TITLE.
  • xonsh no longer backgrounds itself after every command on Cygwin.
  • Fixed an issue about os.killpg() on Cygwin which caused xonsh to crash occasionally
  • Fix crash on startup when Bash Windows Subsystem for Linux is on the Path.
  • Fixed issue with setting and signaling process groups on Linux when the first process is a function alias and has no pid.
  • Fixed _list_completers such that it does not throw a ValueError if no completer is registered.
  • Fixed _list_completers such that it does not throw an AttributeError if a completer has no docstring.
  • Bug that caused command line argument --config-path to be ignored.
  • Bug that caused xonsh to break on startup when prompt-toolkit < 1.0.0.



  • $PROMPT from foreign shells is now ignored.
  • $RC_FILES environment variable now stores the run control files we attempted to load.
  • Only show the prompt for the wizard if we did not attempt to load any run control files (as opposed to if none were successfully loaded).
  • Git and mercurial branch and dirty function refactor to imporve run times.


  • Fixed an issue whereby attempting to delete a literal value (e.g., del 7) in the prompt_toolkit shell would cause xonsh to crash.
  • Fixed broken behavior when using cd .. to move into a nonexistent directory.
  • Partial workaround for Cygwin where pthread_sigmask appears to be missing from the signal module.
  • Fixed crash resulting from malformed $PROMPT.
  • Fixed regression on Windows with the locate_binary() function. The bug prevented source-cmd from working correctly and broke the activate/deactivate aliases for the conda environements.
  • Fixed crash resulting from errors other than syntax errors in run control file.
  • On Windows if bash is not on the path look in the registry for the defaults install directory for GitForWindows.



  • Question mark literals, ?, are now allowed as part of subprocess argument names.
  • IPython style visual pointer to show where syntax error was detected
  • Pretty printing of output and syntax highlighting of input and output can now be controlled via new environment variables $COLOR_INPUT, $COLOR_RESULTS, and $PRETTY_PRINT_RESULTS.
  • In interactive mode, if there are stopped or background jobs, Xonsh prompts for confirmations rather than just killing all jobs and exiting.


  • which now gives a better verbose report of where the executables are found.
  • Tab completion now uses a different interface, which allows new completers to be implemented in Python.
  • Most functions in the Execer now take an extra argument transform, indicating whether the syntax tree transformations should be applied.
  • prompt_toolkit is now loaded lazily, decreasing load times when using the readline shell.
  • RC files are now executed directly in the appropriate context.
  • _ is now updated by ![], to contain the appropriate CompletedCommand object.


  • Fixed bug on Windows where which did not include current directory


  • Fixed crashed bash-completer when bash is not avaiable on Windows
  • Fixed bug on Windows where tab-completion for executables would return all files.
  • Fixed bug on Windows which caused the bash $PROMPT variable to be used when no no $PROMPT variable was set in .xonshrc
  • Improved start-up times by caching information about bash completion functions
  • The –shell-type CLI flag now takes precedence over $SHELL_TYPE specified in .xonshrc
  • Fixed an issue about os.killpg() on OS X which caused xonsh crash with occasionality



  • Fixed PermissionError when tab completions tries to lookup executables in directories without read permissions.
  • Fixed incorrect parsing of command line flags



  • When a subprocess exits with a signal (e.g. SIGSEGV), a message is printed, similar to Bash.
  • Added comma literals to subproc mode.
  • @$(cmd) has been added as a subprocess-mode operator, which replaces in the subprocess command itself with the result of running cmd.
  • New showcmd alias for displaying how xonsh interprets subprocess mode commands and arguments.
  • Added $DYNAMIC_CWD_WIDTH to allow the adjusting of the current working directory width in the prompt.
  • Added $XONSH_DEBUG environment variable to help with debuging.
  • The ${...} shortcut for __xonsh_env__ now returns appropriate completion options


  • On Windows the default bash completions files $BASH_COMPLETIONS now points to the default location of the completions files used by ‘Git for Windows’
  • On Cygwin, some tweaks are applied to foreign shell subprocess calls and the readline import, in order to avoid hangs on launch.


  • Special cased code for handling version of prompt_toolkit < v1.0.0


  • Show sorted bash completions suggestions.
  • Fix bash completions (e.g git etc.) on windows when completions files have spaces in their path names
  • Fixed a bug preventing source-bash from working on Windows
  • Numerous improvements to job control via a nearly-complete rewrite.
  • Addressed issue with finding the next break in subproc mode in context sensitive parsing.
  • Fixed issue with loading readline init files (inputrc) that seems to be triggered by libedit.
  • $MULTILINE_PROMPT now allows colors, as originally intended.
  • Rectified install issue with Jupyter hook when installing with pyenv, Jupyter install hook now repects --prefix argument.
  • Fixed issue with the xonsh.ply subpackage not being installed.
  • Fixed a parsing bug whereby a trailing & on a line was being ignored (processes were unable to be started in the background)



  • and, or, &&, || have been added as subprocess logical operators, by popular demand!
  • Subprocesses may be negated with not and grouped together with parentheses.
  • New framework for writing xonsh extentions, called xontribs.
  • Added a new shell type 'none', used to avoid importing readline or prompt_toolkit when running scripts or running a single command.
  • New: sudo functionality on Windows through an alias
  • Automatically enhance colors for readability in the default terminal (cmd.exe) on Windows. This functionality can be enabled/disabled with the $INTENSIFY_COLORS_ON_WIN environment variable.
  • Added Ellipsis lookup to __xonsh_env__ to allow environment variable checks, e.g. 'HOME' in ${...}
  • Added an option to update os.environ every time the xonsh environment changes. This is disabled by default but can be enabled by setting $UPDATE_OS_ENVIRON to True.
  • Added Windows ‘cmd.exe’ as a foreign shell. This gives xonsh the ability to source Windows Batch files (.bat and .cmd). Calling source-cmd script.bat or the alias source-bat script.bat will call the bat file and changes to the environment variables will be reflected in xonsh.
  • Added an alias for the conda environment activate/deactivate batch scripts when running the Anaconda python distribution on Windows.
  • Added a menu entry to launch xonsh when installing xonsh from a conda package
  • Added a new which alias that supports both regular which and also searches through xonsh aliases. A pure python implementation of which is used. Thanks to Trent Mick. https://github.com/trentm/which/
  • Added support for prompt toolkit v1.0.0.
  • Added $XONSH_CACHE_SCRIPTS and $XONSH_CACHE_EVERYTHING environment variables to control caching of scripts and interactive commands. These can also be controlled by command line options --no-script-cache and --cache-everything when starting xonsh.
  • Added a workaround to allow ctrl-c to interrupt reverse incremental search in the readline shell


  • Running scripts through xonsh (or running a single command with -c) no longer runs the user’s rc file, unless the --login option is specified. Also avoids loading aliases and environments from foreign shells, as well as loading bash completions.
  • rc files are now compiled and cached, to avoid re-parsing when they haven’t changed. Scripts are also compiled and cached, and there is the option to cache interactive commands.
  • Left and Right arrows in the prompt_toolkit shell now wrap in multiline environments
  • Regexpath matching with backticks, now returns an empty list in python mode.
  • Pygments added as a dependency for the conda package
  • Foreign shells now allow for setting exit-on-error commands before and after all other commands via the seterrprevcmd and seterrpostcmd arguments. Sensinble defaults are provided for existing shells.
  • PLY is no longer a external dependency but is bundled in xonsh/ply. Xonsh can therefore run without any external dependencies, although having prompt-toolkit recommended.
  • Provide better user feedback when running which in a platform that doesn’t provide it (e.g. Windows).
  • The lexer now uses a custom tokenizer that handles regex globs in the proper way.


  • Fixed bug with loading prompt-toolkit shell < v0.57.
  • Fixed bug with prompt-toolkit completion when the cursor is not at the end of the line.
  • Aliases will now evaluate enviornment variables and other expansions at execution time rather than passing through a literal string.
  • Fixed environment variables from os.environ not beeing loaded when a running a script
  • The readline shell will now load the inputrc files.
  • Fixed bug that prevented source-alias from working.
  • Now able to ^C the xonfig wizard on start up.
  • Fixed deadlock on Windows when runing subprocess that generates enough output to fill the OS pipe buffer.
  • Sourcing foreign shells will now return a non-zero exit code if the source operation failed for some reason.
  • Fixed PermissionError when running commands in directories without read permissions
  • Prevent Windows fixups from overriding environment vars in static config
  • Fixed Optional Github project status to reflect added/removed files via git_dirty_working_directory()
  • Fixed xonsh.exe launcher on Windows, when Python install directory has a space in it
  • Fixed $CDPATH to support ~ and environments variables in its items



  • Added new valid $SHELL_TYPE called 'best'. This selects the best value for the concrete shell type based on the availability on the user’s machine.
  • New environment variable $XONSH_COLOR_STYLE will set the color mapping for all of xonsh.
  • New XonshStyle pygments style will determine the approriate color mapping based on $XONSH_COLOR_STYLE. The associated xonsh_style_proxy() is intended for wrapping XonshStyle when actually being used by pygments.
  • The functions print_color() and format_color() found in xonsh.tools dispatch to the approriate shell color handling and may be used from anywhere.
  • xonsh.tools.HAVE_PYGMENTS flag now denotes if pygments is installed and available on the users system.
  • The ansi_colors module is now availble for handling ANSI color codes.
  • ? and ?? operator output now has colored titles, like in IPython.
  • ?? will syntax highlight source code if pygments is available.
  • Python mode output is now syntax highlighted if pygments is available.
  • New $RIGHT_PROMPT environment variable for displaying right-aligned text in prompt-toolkit shell.
  • Added !(...) operator, which returns an object representing the result of running a command. The truth value of this object is True if the return code is equal to zero and False otherwise.
  • Optional dependency on the win_unicode_console package to enable unicode support in cmd.exe on Windows. This can be disabled/enabled with the $WIN_UNICODE_CONSOLE environment variable.


  • Updated $SHELL_TYPE default to 'best'.
  • Shell classes are now responsible for implementing their own color formatting and printing.
  • Prompt coloring, history diffing, and tracing uses new color handling capabilities.
  • New Token.Color token for xonsh color names, e.g. we now use Token.Color.RED rather than Token.RED.
  • Untracked files in git are ignored when determining if a git workdir is is dirty. This affects the coloring of the branch label.
  • Regular expression globbing now uses re.fullmatch instead of re.match, and the result of an empty regex glob does not cause the argument to be deleted.


  • The xonsh.tools.TERM_COLORS mapping has been axed, along with all references to it. This may cause a problem if you were using a raw color code in your xonshrc file from $FORMATTER_DICT. To fix, simply remove these references.


  • Multidimensional slicing, as in numpy, no longer throws SyntaxErrors.
  • Some minor zsh fixes for more platforms and setups.
  • The BaseShell.settitle method no longer has its commands captured by $(...)



  • trace alias added that enables users to turn on and off the printing of source code lines prior to their execution. This is useful for debugging scripts.
  • New ability to force callable alias functions to be run in the foreground, i.e. the main thread from which the function was called. This is useful for debuggers and profilers which may require such access. Use the xonsh.proc.foreground decorator on an alias function to flag it. ForegroundProcProxy and SimpleForegroundProcProxy classes have been added to support this feature. Normally, forcing a foreground alias is not needed.
  • Added boolean $RAISE_SUBPROC_ERROR environment variable. If true and a subprocess command exits with a non-zero return code, a CalledProcessError will be raised. This is useful in scripts that should fail at the first error.
  • If the setproctitle package is installed, the process title will be set to 'xonsh' rather than the path to the Python interpreter.
  • zsh foreign shell interface now supported natively in xonsh, like with Bash. New source-zsh alias allows easy access to zsh scripts and functions.
  • Vox virtual environment manager added.


  • The foreign_shell_data() keyword arguments envcmd and aliascmd now default to None.
  • Updated alias docs to pull in usage from the commands automatically.


  • Hundreds of bugs related to line and column numbers have been addressed.
  • Fixed path completion not working for absolute paths or for expanded paths on Windows.
  • Fixed issue with hg dirty branches and $PATH.
  • Fixed issues related to foreign shell data in files with whitespace in the names.
  • Worked around bug in ConEmu/cmder which prevented get_git_branch() from working in these terminal emulators on Windows.



  • New configuration utility ‘xonfig’ which reports current system setup information and creates config files through an interactive wizard.
  • Toolkit for creating wizards now available
  • timeit and which aliases will now complete their arguments.
  • $COMPLETIONS_MENU_ROWS environment variable controls the size of the tab-completion menu in prompt-toolkit.
  • Prompt-toolkit shell now supports true multiline input with the ability to scroll up and down in the prompt.


  • The xonfig wizard will run on interactive startup if no configuration file is found.
  • BaseShell now has a singleline() method for prompting a single input.
  • Environment variable docs are now auto-generated.
  • Prompt-toolkit shell will now dynamically allocate space for the tab-completion menu.
  • Looking up nonexistent environment variables now generates an error in Python mode, but produces a sane default value in subprocess mode.
  • Environments are now considered to contain all manually-adjusted keys, and also all keys with an associated default value.


  • Removed xonsh.ptk.shortcuts.Prompter.create_prompt_layout() and xonsh.ptk.shortcuts.Prompter.create_prompt_application() methods to reduce portion of xonsh that forks prompt-toolkit. This may require users to upgrade to prompt-toolkit v0.57+.


  • First prompt in the prompt-toolkit shell now allows for up and down arrows to search through history.
  • Made obtaining the prompt-toolkit buffer thread-safe.
  • Now always set non-detypable environment variables when sourcing foreign shells.
  • Fixed issue with job management if a TTY existed but was not controlled by the process, posix only.
  • Jupyter kernel no longer times out when using foreign shells on startup.
  • Capturing redirections, e.g. $(echo hello > f.txt), no longer fails with a decoding error.
  • Evaluation in a Jupyter cell will return pformatted object.
  • Jupyter with redirect uncaptured subprocs to notebook.
  • Tab completion in Jupyter fixed.

v0.2.1 - v0.2.4

You are reading the docs...but you still feel hungry.



  • Rich history recording and replaying



  • Naturally typed environment variables
  • Inherits the environment from BASH
  • Uses BASH completion for subprocess commands
  • Regular expression filename globbing
  • Its own PLY-based lexer and parser
  • xonsh code parses into a Python AST
  • You can do all the normal Python things, like arithmetic and importing
  • Captured and uncaptured subprocesses
  • Pipes, redirection, and non-blocking subprocess syntax support
  • Help and superhelp with ? and ??
  • Command aliasing
  • Multiline input, unlike ed
  • History matching like in IPython
  • Color prompts
  • Low system overhead


The before times, like 65,000,000 BCE.