我有一个脚本,其中我尝试使用subprocess.call来执行一系列shell命令,但执行时似乎省略了一些命令。
具体做法是:
#!/usr/bin/python
import tempfile
import subprocess
import os
import re
grepfd, grepfpath = tempfile.mkstemp(suffix=".xx")
sedfd, sedfpath = tempfile.mkstemp(suffix=".xx")
# grepoutfile = open( grepfpath, 'w')
sedoutfile = open( sedfpath, 'w' )
subprocess.call(['cp','/Users/bobby/Downloads/sample.txt', grepfpath])
sedcmd = [ 'sort',
grepfpath,
'|',
'uniq',
'|',
'sed',
'-e',
'"s/bigstring of word/ smaller /"',
'|',
'column',
'-t',
'-s',
'"=>"' ]
print "sedcmd = ", sedcmd
subprocess.call( ['ls', grepfpath ] )
subprocess.call( ['sort', '|', 'uniq' ], stdin = grepfd )
subprocess.call( sedcmd, stdout = sedoutfile )
它会将其生成为输出:
python d3.py
sedcmd = ['sort',/ var / folder / 3h / _0xwt5bx0hx8tgx06cmq9h_4f183ql / T / tmp5Gp0ff.xx','|','uniq','|','sed',' - e','“s / bigstring of word / smaller /“','|','column',' - t',' - s','”=>“']
/var/folders/3h/_0xwt5bx0hx8tgx06cmq9h_4f183ql/T/tmp5Gp0ff.xx
sort:open failed:|:没有这样的文件或目录
sort:无效选项 - e
尝试`sort --help'获取更多信息。
第一个'排序:打开失败:|:没有这样的文件......来自第一个子进程调用['sort','|','uniq'],stdin = grepfd) 'sort:invalid选项 - e ..来自第二个子进程调用(sedcmd)。
我已经看到很多在这种情况下使用管道的例子 - 所以我做错了什么? 谢谢!
答案 0 :(得分:2)
这是一个将运行具有任意数量管道的命令的类:
<强> pipeline.py 强>
import shlex
import subprocess
class Pipeline(object):
def __init__(self, command):
self.command = command
self.command_list = self.command.split('|')
self.output = None
self.errors = None
self.status = None
self.result = None
def run(self):
process_list = list()
previous_process = None
for command in self.command_list:
args = shlex.split(command)
if previous_process is None:
process = subprocess.Popen(args, stdout=subprocess.PIPE)
else:
process = subprocess.Popen(args,
stdin=previous_process.stdout,
stdout=subprocess.PIPE)
process_list.append(process)
previous_process = process
last_process = process_list[-1]
self.output, self.errors = last_process.communicate()
self.status = last_process.returncode
self.result = (0 == self.status)
return self.result
此示例显示如何使用该类:
<强> harness.py 强>
from pipeline import Pipeline
if __name__ == '__main__':
command = '|'.join([
"sort %s",
"uniq",
"sed -e 's/bigstring of word/ smaller /'",
"column -t -s '=>'"
])
command = command % 'sample.txt'
pipeline = Pipeline(command)
if not pipeline.run():
print "ERROR: Pipeline failed"
else:
print pipeline.output
我创建了此示例文件以进行测试:
<强> sample.txt的强>
word1>word2=word3
list1>list2=list3
a>bigstring of word=b
blah1>blah2=blah3
<强>输出强>
a smaller b
blah1 blah2 blah3
list1 list2 list3
word1 word2 word3
答案 1 :(得分:0)
因此,如果在命令中要使用shell管道,则可以在子进程中添加shell = True: 所以它会是这样的:
sedcmd = 'sort /var/folders/3h/_0xwt5bx0hx8tgx06cmq9h_4f183ql/T/tmp5Gp0ff.xx | uniq | sed -e "s/bigstring of word/ smaller /" | column -t -s "=>" '
subprocess.call(sedcmd, shell=True)
但要小心 shell = True ,强烈劝阻才能使用它:subprocess official documentation
因此,如果你想使用没有shell = True的管道,你可以在stdout中使用subprocees.PIPE,这里有一个如何做的例子:stackoveflow answer