将命令重定向到 Python 中另一个命令的输入

发布于 2024-07-06 10:58:08 字数 667 浏览 8 评论 0原文

我想在 python 中复制此内容：

gvimdiff <(hg cat file.txt) file.txt

（hg cat file.txt 输出 file.txt 最近提交的版本）

我知道如何将文件通过管道传输到 gvimdiff，但它不会接受另一个文件：

$ hg cat file.txt | gvimdiff file.txt -
Too many edit arguments: "-"

进入 python 部分...

# hgdiff.py
import subprocess
import sys
file = sys.argv[1]
subprocess.call(["gvimdiff", "<(hg cat %s)" % file, file])

当子进程被调用时，它只是将 <(hg cat file) 作为文件名传递到 gvimdiff 上。

那么，有没有办法像 bash 那样重定向命令呢？为了简单起见，只需 cat 一个文件并将其重定向到 diff：

diff <(cat file.txt) file.txt

原文

I would like to replicate this in python:

gvimdiff <(hg cat file.txt) file.txt

(hg cat file.txt outputs the most recently committed version of file.txt)

I know how to pipe the file to gvimdiff, but it won't accept another file:

$ hg cat file.txt | gvimdiff file.txt -
Too many edit arguments: "-"

Getting to the python part...

# hgdiff.py
import subprocess
import sys
file = sys.argv[1]
subprocess.call(["gvimdiff", "<(hg cat %s)" % file, file])

When subprocess is called it merely passes <(hg cat file) onto gvimdiff as a filename.

So, is there any way to redirect a command as bash does?
For simplicity's sake just cat a file and redirect it to diff:

diff <(cat file.txt) file.txt

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寄与心 2024-07-13 10:58:08

可以办到。然而，从 Python 2.5 开始，这种机制是 Linux 特定的并且不可移植：

import subprocess
import sys

file = sys.argv[1]
p1 = subprocess.Popen(['hg', 'cat', file], stdout=subprocess.PIPE)
p2 = subprocess.Popen([
    'gvimdiff',
    '/proc/self/fd/%s' % p1.stdout.fileno(),
    file])
p2.wait()

也就是说，在 diff 的特定情况下，您可以简单地从 stdin 中获取其中一个文件，并且无需使用类似于 bash 的功能问题：

file = sys.argv[1]
p1 = subprocess.Popen(['hg', 'cat', file], stdout=subprocess.PIPE)
p2 = subprocess.Popen(['diff', '-', file], stdin=p1.stdout)
diff_text = p2.communicate()[0]

It can be done. As of Python 2.5, however, this mechanism is Linux-specific and not portable:

import subprocess
import sys

file = sys.argv[1]
p1 = subprocess.Popen(['hg', 'cat', file], stdout=subprocess.PIPE)
p2 = subprocess.Popen([
    'gvimdiff',
    '/proc/self/fd/%s' % p1.stdout.fileno(),
    file])
p2.wait()

That said, in the specific case of diff, you can simply take one of the files from stdin, and remove the need to use the bash-alike functionality in question:

file = sys.argv[1]
p1 = subprocess.Popen(['hg', 'cat', file], stdout=subprocess.PIPE)
p2 = subprocess.Popen(['diff', '-', file], stdin=p1.stdout)
diff_text = p2.communicate()[0]

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偏爱自由 2024-07-13 10:58:08

还有命令模块：

import commands

status, output = commands.getstatusoutput("gvimdiff <(hg cat file.txt) file.txt")

如果您想在命令运行时实际获取命令中的数据，还有 popen 函数集。

There is also the commands module:

import commands

status, output = commands.getstatusoutput("gvimdiff <(hg cat file.txt) file.txt")

There is also the popen set of functions, if you want to actually grok the data from a command as it is running.

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情话已封尘 2024-07-13 10:58:08

这实际上是 docs 中的一个示例：

p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]

这对您来说意味着：

import subprocess
import sys

file = sys.argv[1]
p1 = Popen(["hg", "cat", file], stdout=PIPE)
p2 = Popen(["gvimdiff", "file.txt"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]

这会删除使用特定于 Linux 的 /proc/self/fd 位，使其可以在其他 unice 上工作，例如 Solaris 和 BSD（包括 MacOS），甚至可以在 Windows 上工作。

This is actually an example in the docs:

p1 = Popen(["dmesg"], stdout=PIPE)
p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]

which means for you:

import subprocess
import sys

file = sys.argv[1]
p1 = Popen(["hg", "cat", file], stdout=PIPE)
p2 = Popen(["gvimdiff", "file.txt"], stdin=p1.stdout, stdout=PIPE)
output = p2.communicate()[0]

This removes the use of the linux-specific /proc/self/fd bits, making it probably work on other unices like Solaris and the BSDs (including MacOS) and maybe even work on Windows.

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