plumbum 1.8.3

基础

>>> from plumbum import local
>>> local.cmd.ls
LocalCommand(/bin/ls)
>>> local.cmd.ls()
'build.py\nCHANGELOG.rst\nconda.recipe\nCONTRIBUTING.rst\ndocs\nexamples\nexperiments\nLICENSE\nMANIFEST.in\nPipfile\nplumbum\nplumbum.egg-info\npytest.ini\nREADME.rst\nsetup.cfg\nsetup.py\ntests\ntranslations.py\n'
>>> notepad = local["c:\\windows\\notepad.exe"]
>>> notepad()                                   # Notepad window pops up
''                                              # Notepad window is closed by user, command returns

在上面的示例中，如果您有一个不寻常命名的可执行文件或可执行文件的完整路径，可以使用local["ls"]。local对象代表您的本地计算机。您将看到，Plumbum还提供了使用相同API的远程计算机！您还可以使用from plumbum.cmd import ls来访问PATH中的程序。

管道

>>> from plumbum.cmd import ls, grep, wc
>>> chain = ls["-a"] | grep["-v", r"\.py"] | wc["-l"]
>>> print(chain)
/bin/ls -a | /bin/grep -v '\.py' | /usr/bin/wc -l
>>> chain()
'27\n'

重定向

>>> from plumbum.cmd import cat, head
>>> ((cat < "setup.py") | head["-n", 4])()
'#!/usr/bin/env python3\nimport os\n\ntry:\n'
>>> (ls["-a"] > "file.list")()
''
>>> (cat["file.list"] | wc["-l"])()
'31\n'

工作目录操作

>>> local.cwd
<LocalWorkdir /home/tomer/workspace/plumbum>
>>> with local.cwd(local.cwd / "docs"):
...     chain()
...
'22\n'

前台和后台执行

>>> from plumbum import FG, BG
>>> (ls["-a"] | grep[r"\.py"]) & FG         # The output is printed to stdout directly
build.py
setup.py
translations.py
>>> (ls["-a"] | grep[r"\.py"]) & BG         # The process runs "in the background"
<Future ['/bin/grep', '\\.py'] (running)>

命令嵌套

>>> from plumbum.cmd import sudo, ifconfig
>>> 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

远程命令（通过SSH）

支持openSSH-兼容客户端，PuTTY（在Windows上）和Paramiko（SSH2的纯Python实现）

>>> 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'

CLI应用程序

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()

$ 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')