Plumbum: Shell Combinators and More¶
Ever wished the compactness of shell scripts be put into a real programming language? Say hello to Plumbum Shell Combinators. Plumbum (Latin for lead, which was used to create pipes back in the day) is a small yet feature-rich library for shell script-like programs in Python. The motto of the library is “Never write shell scripts again”, and thus it attempts to mimic the shell syntax (shell combinators) where it makes sense, while keeping it all Pythonic and cross-platform.
Apart from shell-like syntax and handy shortcuts, the library provides local and remote command execution (over SSH), local and remote file-system paths, easy working-directory and environment manipulation, quick access to ANSI colors, and a programmatic Command-Line Interface (CLI) application toolkit. Now let’s see some code!
News¶
2023.10.05: Version 1.9.0 released with Python 3.8-3.13 support, and some small fixes.
2024.04.29: Version 1.8.3 released with some small fixes, final version to support Python 3.6 and 3.7.
2023.05.30: Version 1.8.2 released with a PyPI metadata fix, Python 3.12b1 testing, and a bit more typing.
2023.01.01: Version 1.8.1 released with hatchling replacing setuptools for the build system, and support for Path objects in local.
2022.10.05: Version 1.8.0 released with
NO_COLOR
/FORCE_COLOR
,all_markers
& future annotations for the CLI, some command enhancements, & Python 3.11 testing.2021.12.23: Version 1.7.2 released with very minor fixes, final version to support Python 2.7 and 3.5.
2021.11.23: Version 1.7.1 released with a few features like reverse tunnels, color group titles, and a glob path fix. Better Python 3.10 support.
2021.02.08: Version 1.7.0 released with a few new features like
.with_cwd
, some useful bugfixes, and lots of cleanup.2020.03.23: Version 1.6.9 released with several Path fixes, final version to support Python 2.6.
2019.10.30: Version 1.6.8 released with
local.cmd
, a few command updates,Set
improvements, andTypedEnv
.2018.08.10: Version 1.6.7 released with several minor additions, mostly to CLI apps, and
run_*
modifiers added.2018.02.12: Version 1.6.6 released with one more critical bugfix for a error message regression in 1.6.5.
2017.12.29: Version 1.6.5 released with mostly bugfixes, including a critical one that could break pip installs on some platforms. English cli apps now load as fast as before the localization update.
2017.11.27: Version 1.6.4 released with new CLI localization support. Several bugfixes and better pathlib compatibility, along with better separation between Plumbum’s internal packages.
2016.12.31: Version 1.6.3 released to provide Python 3.6 compatibility. Mostly bugfixes, several smaller improvements to paths, and a provisional config parser added.
2016.12.3: Version 1.6.2 is now available through conda-forge, as well.
2016.6.25: Version 1.6.2 released. This is mostly a bug fix release, but a few new features are included. Modifiers allow some new arguments, and
Progress
is improved. Better support for SunOS and other OS’s.2015.12.18: Version 1.6.1 released. The release mostly contains smaller fixes for CLI, 2.6/3.5 support, and colors. PyTest is now used for tests, and Conda is supported.
2015.10.16: Version 1.6.0 released. Highlights include Python 3.5 compatibility, the
plumbum.colors
package,Path
becoming a subclass ofstr
and a host of bugfixes. Special thanks go to Henry for his efforts.2015.07.17: Version 1.5.0 released. This release brings a host of bug fixes, code cleanups and some experimental new features (be sure to check the changelog). Also, say hi to Henry Schreiner, who has joined as a member of the project.
Cheat Sheet¶
Basics¶
>>> from plumbum import local
>>> ls = local["ls"]
>>> ls
LocalCommand(<LocalPath /bin/ls>)
>>> ls()
'build.py\ndist\ndocs\nLICENSE\nplumbum\nREADME.rst\nsetup.py\ntests\ntodo.txt\n'
>>> notepad = local["c:\\windows\\notepad.exe"]
>>> notepad() # Notepad window pops up
'' # Notepad window is closed by user, command returns
Instead of writing xxx = local["xxx"]
for every program you wish to use, you can
also import commands:
>>> from plumbum.cmd import grep, wc, cat, head
>>> grep
LocalCommand(<LocalPath /bin/grep>)
Or, use the local.cmd
syntactic-sugar:
>>> local.cmd.ls
LocalCommand(<LocalPath /bin/ls>)
>>> local.cmd.ls()
'build.py\ndist\ndocs\nLICENSE\nplumbum\nREADME.rst\nsetup.py\ntests\ntodo.txt\n'
See Local Commands.
Piping¶
>>> chain = ls["-a"] | grep["-v", "\\.py"] | wc["-l"]
>>> print(chain)
/bin/ls -a | /bin/grep -v '\.py' | /usr/bin/wc -l
>>> chain()
'13\n'
See Pipelining.
Redirection¶
>>> ((cat < "setup.py") | head["-n", 4])()
'#!/usr/bin/env python3\nimport os\n\ntry:\n'
>>> (ls["-a"] > "file.list")()
''
>>> (cat["file.list"] | wc["-l"])()
'17\n'
Working-directory manipulation¶
>>> local.cwd
<Workdir /home/tomer/workspace/plumbum>
>>> with local.cwd(local.cwd / "docs"):
... chain()
...
'15\n'
A more explicit, and thread-safe way of running a command in a different directory is using the .with_cwd()
method:
.. code-block:: python
>>> ls_in_docs = local.cmd.ls.with_cwd("docs")
>>> ls_in_docs()
'api\nchangelog.rst\n_cheatsheet.rst\ncli.rst\ncolorlib.rst\n_color_list.html\ncolors.rst\nconf.py\nindex.rst\nlocal_commands.rst\nlocal_machine.rst\nmake.bat\nMakefile\n_news.rst\npaths.rst\nquickref.rst\nremote.rst\n_static\n_templates\ntyped_env.rst\nutils.rst\n'
See Paths and The Local Object.
Foreground and background execution¶
>>> from plumbum import FG, BG
>>> (ls["-a"] | grep["\\.py"]) & FG # The output is printed to stdout directly
build.py
.pydevproject
setup.py
>>> (ls["-a"] | grep["\\.py"]) & BG # The process runs "in the background"
<Future ['/bin/grep', '\\.py'] (running)>
Command nesting¶
>>> from plumbum.cmd import sudo
>>> print(sudo[ifconfig["-a"]])
/usr/bin/sudo /sbin/ifconfig -a
>>> (sudo[ifconfig["-a"]] | grep["-i", "loop"]) & FG
lo Link encap:Local Loopback
UP LOOPBACK RUNNING MTU:16436 Metric:1
See Command Nesting.
Remote commands (over SSH)¶
Supports openSSH-compatible clients, PuTTY (on Windows) and Paramiko (a pure-Python implementation of SSH2):
>>> from plumbum import SshMachine
>>> remote = SshMachine("somehost", user = "john", keyfile = "/path/to/idrsa")
>>> r_ls = remote["ls"]
>>> with remote.cwd("/lib"):
... (r_ls | grep["0.so.0"])()
...
'libusb-1.0.so.0\nlibusb-1.0.so.0.0.0\n'
See Remote.
CLI applications¶
import logging
from plumbum import cli
class MyCompiler(cli.Application):
verbose = cli.Flag(["-v", "--verbose"], help = "Enable verbose mode")
include_dirs = cli.SwitchAttr("-I", list = True, help = "Specify include directories")
@cli.switch("-loglevel", int)
def set_log_level(self, level):
"""Sets the log-level of the logger"""
logging.root.setLevel(level)
def main(self, *srcfiles):
print("Verbose:", self.verbose)
print("Include dirs:", self.include_dirs)
print("Compiling:", srcfiles)
if __name__ == "__main__":
MyCompiler.run()
Sample output¶
$ python3 simple_cli.py -v -I foo/bar -Ispam/eggs x.cpp y.cpp z.cpp
Verbose: True
Include dirs: ['foo/bar', 'spam/eggs']
Compiling: ('x.cpp', 'y.cpp', 'z.cpp')
Colors and Styles¶
from plumbum import colors
with colors.red:
print("This library provides safe, flexible color access.")
print(colors.bold | "(and styles in general)", "are easy!")
print("The simple 16 colors or",
colors.orchid & colors.underline | '256 named colors,',
colors.rgb(18, 146, 64) | "or full rgb colors" ,
'can be used.')
print("Unsafe " + colors.bg.dark_khaki + "color access" + colors.bg.reset + " is available too.")
Sample output¶
This library provides safe color access.
Color (and styles in general) are easy!
The simple 16 colors, 256 named colors, or full hex colors can be used.
Unsafe color access is available too.
See Colors.
Development and Installation¶
The library is developed on GitHub, and will happily accept patches from users. Please use the GitHub’s built-in issue tracker to report any problem you encounter or to request features. The library is released under the permissive MIT license.
Requirements¶
Plumbum supports Python 3.6-3.10 and PyPy and is continually tested on
Linux, Mac, and Windows machines through GitHub Actions. Any Unix-like machine
should work fine out of the box, but on Windows, you’ll probably want to
install a decent coreutils
environment and add it to your PATH
, or use WSL(2). I can recommend mingw (which comes bundled with Git for Windows), but cygwin should
work too. If you only wish to use Plumbum as a Popen-replacement to run Windows
programs, then there’s no need for the Unix tools.
Note that for remote command execution, an openSSH-compatible client is
required (also bundled with Git for Windows), and a bash
-compatible shell
and a coreutils environment is also expected on the host machine.
This project uses setuptools
to build wheels; and setuptools_scm
is
required for building SDists. These dependencies will be handled for you by PEP
518 compatible builders, like build and pip 10+
.
Download¶
You can download the library from the Python Package Index (in a variety of formats), or
run pip install plumbum
directly. If you use Anaconda, you can also get it
from the conda-forge
channel with conda install -c conda-forge plumbum
.
User Guide¶
The user guide covers most of the features of Plumbum, with lots of code-snippets to get you swimming in no time. It introduces the concepts and “syntax” gradually, so it’s recommended you read it in order. A quick reference guide is available.
API Reference¶
The API reference (generated from the docstrings within the library) covers all of the exposed APIs of the library. Note that some “advanced” features and some function parameters are missing from the guide, so you might want to consult with the API reference in these cases.
- Package plumbum.cli
ShowHelp
ShowHelpAll
ShowVersion
Application
SwitchError
PositionalArgumentsError
SwitchCombinationError
UnknownSwitch
MissingArgument
MissingMandatorySwitch
WrongArgumentType
SubcommandError
switch()
autoswitch()
SwitchAttr
Flag
CountOf
positional
Validator
Range
Set
Predicate
- Terminal-related utilities
readline()
ask()
choose()
prompt()
get_terminal_size()
Progress
- Terminal size utility
get_terminal_size()
- Progress bar
ProgressBase
Progress
ProgressIPy
ProgressAuto
- Package plumbum.commands
iter_lines()
run_proc()
shquote()
RedirectionError
BaseCommand
Pipeline
BaseRedirection
BoundCommand
BoundEnvCommand
ConcreteCommand
StdinRedirection
StdoutRedirection
StderrRedirection
AppendingStdoutRedirection
StdinDataRedirection
Future
PipeToLoggerMixin
ProcessExecutionError
ProcessTimedOut
ProcessLineTimedOut
CommandNotFound
run_proc()
iter_lines()
- Package plumbum.machines
- Package plumbum.path
- Package plumbum.fs
- Package plumbum.colors
- Colorlib design
Note
The local
object is an instance of a machine
.
About¶
The original purpose of Plumbum was to enable local and remote program execution with ease, assuming nothing fancier than good-old SSH. On top of this, a file-system abstraction layer was devised, so that working with local and remote files would be seamless.
I’ve toyed with this idea for some time now, but it wasn’t until I had to write build scripts
for a project I’ve been working on that I decided I’ve had it with shell scripts and it’s time
to make it happen. Plumbum was born from the scraps of the Path
class, which I
wrote for the aforementioned build system, and the SshContext
and SshTunnel
classes
that I wrote for RPyC. When I combined the two with shell combinators
(because shell scripts do have an edge there) the magic happened and here we are.
Credits¶
The project has been inspired by PBS (now called sh) of Andrew Moffat, and has borrowed some of his ideas (namely treating programs like functions and the nice trick for importing commands). However, I felt there was too much magic going on in PBS, and that the syntax wasn’t what I had in mind when I came to write shell-like programs. I contacted Andrew about these issues, but he wanted to keep PBS this way. Other than that, the two libraries go in different directions, where Plumbum attempts to provide a more wholesome approach.
Plumbum also pays tribute to Rotem Yaari who suggested a
library code-named pyplatform
for that very purpose, but which had never materialized.