如何将subprocess.call()输出推到终端和文件？

Question

我有subprocess.call(["ddrescue", in_file_path, out_file_path], stdout=drclog)。我想让它在终端运行时显示这个dd救援，并将输出写到drclog文件中。我尝试过使用subprocess.call(["ddrescue", in_file_path, out_file_path], stdout=drclog, shell=True)，但是这给了我一个输入错误。

Answer 1

如果ddrescue的stdout/stderr重定向到管道，那么可以使用tee实用程序在终端上显示输出并将其保存到文件中：

$ ddrescue input_path output_path ddrescue_logfile |& tee logfile

如果是这样，那么您可以尝试使用script实用程序提供一个伪tty：

$ script -c 'ddrescue input_path output_path ddrescue_logfile' -q logfile

如果是it writes directly to a terminal，那么可以使用screen捕获输出：

$ screen -L -- ddrescue input_path output_path ddrescue_logfile

默认情况下，输出保存在screenlog.0文件中。

要在Python中模拟tee-based命令而不调用tee实用程序：

#!/usr/bin/env python3
import shlex
import sys
from subprocess import Popen, PIPE, STDOUT

command = 'ddrescue input_path output_path ddrescue_logfile'
with Popen(shlex.split(command), stdout=PIPE, stderr=STDOUT, bufsize=1) as p:
    with open('logfile', 'wb') as logfile:
        for line in p.stdout:
            logfile.write(line)
            sys.stdout.buffer.write(line)
            sys.stdout.buffer.flush()

在Python中使用tee-based命令调用shell=True

#!/usr/bin/env python
from pipes import quote
from subprocess import call

files = input_path, output_path, ddrescue_logfile
rc = call('ddrescue {} |  tee -a drclog'.format(' '.join(map(quote, files))),
          shell=True)

要模仿script-based命令：

#!/usr/bin/env python3
import os
import shlex
import pty

logfile = open('logfile', 'wb')
def read(fd):
    data = os.read(fd, 1024) # doesn't block, it may return less
    logfile.write(data) # it can block but usually not for long
    return data
command = 'ddrescue input_path output_path ddrescue_logfile'
status = pty.spawn(shlex.split(command), read)
logfile.close()

要在Python中调用screen命令：

#!/usr/bin/env python3
import os
import shlex
from subprocess import check_call

screen_cmd = 'screen -L -- ddrescue input_path output_path ddrescue_logfile'
check_call(shlex.split(screen_cmd))
os.replace('screenlog.0', 'logfile')

Answer 2

对我有效的解决方案是subprocess.call(["ddrescue $0 $1 | tee -a drclog", in_file_path, out_file_path], shell=True)。