模拟bash进程替换：
#!/usr/bin/env pythonfrom subprocess import check_callcheck_call('someprogram <(someprocess) <(anotherprocess)',shell=True, executable='/bin/bash')在Python中，您可以使用命名管道：
#!/usr/bin/env pythonfrom subprocess import Popenwith named_pipes(n=2) as paths: someprogram = Popen(['someprogram'] + paths) processes = [] for path, command in zip(paths, ['someprocess', 'anotherprocess']): with open(path, 'wb', 0) as pipe: processes.append(Popen(command, stdout=pipe, close_fds=True)) for p in [someprogram] + processes: p.wait()
在哪里
named_pipes(n)：
import osimport shutilimport tempfilefrom contextlib import contextmanager@contextmanagerdef named_pipes(n=1): dirname = tempfile.mkdtemp() try: paths = [os.path.join(dirname, 'named_pipe' + str(i)) for i in range(n)] for path in paths: os.mkfifo(path) yield paths finally: shutil.rmtree(dirname)
实现bash进程替换的另一种更可取的方式（无需在磁盘上创建命名条目）是使用@Dunes建议的
/dev/fd/N文件名（如果可用）。在FreeBSD上，（）为进程打开的所有文件描述符创建条目。要测试可用性，请运行：
fdescfs(5)
/dev/fd/#
$ test -r /dev/fd/3 3</dev/null && echo /dev/fd is available
如果失败；尝试进行符号链接
/dev/fd，
proc(5)就像在某些Linux上所做的那样：
$ ln -s /proc/self/fd /dev/fd
这是
/dev/fd基于
someprogram <(someprocess) <(anotherprocess)bash命令的实现：
#!/usr/bin/env python3from contextlib import ExitStackfrom subprocess import CalledProcessError, Popen, PIPEdef kill(process): if process.poll() is None: # still running process.kill()with ExitStack() as stack: # for proper cleanup processes = [] for command in [['someprocess'], ['anotherprocess']]: # start child processes processes.append(stack.enter_context(Popen(command, stdout=PIPE))) stack.callback(kill, processes[-1]) # kill on someprogram exit fds = [p.stdout.fileno() for p in processes] someprogram = stack.enter_context( Popen(['someprogram'] + ['/dev/fd/%d' % fd for fd in fds], pass_fds=fds)) for p in processes: # close pipes in the parent p.stdout.close()# exit stack: wait for processesif someprogram.returnpre != 0: # errors shouldn't go unnoticed raise CalledProcessError(someprogram.returnpre, someprogram.args)
注意：在我的Ubuntu机器上，该
subprocess代码仅在Python 3.4+中有效，尽管
pass_fds自Python 3.2起可用。
