使用python子进程执行awk命令

Question

I am trying to extract year field from "date" output Code:

import sys
import os
import subprocess
per_name = input('Enter name:')
age = input('Enter age:')
to_date = subprocess.Popen(["date"],stdout=subprocess.PIPE)
date = subprocess.Popen(['awk',"'{print","$NF}'"],stdin=to_date.stdout)
act_date = date.communicate()
to_date=str(act_date)
print("Year: "+act_date)

I am getting following error:

awk: syntax error at source line 1
context is
 >>> ' <<< 
missing }
awk: bailing out at source line 1
Traceback (most recent call last):
File "pyt_ex1.py", line 10, in <module>
print("Year: "+act_date)

Please help me with right way of extracting it using 'awk'

Answer 1

Why are you trying to use awk for this? python's str.split() will split the input by spaces, doing the same thing as awk.

year = date_string.split()[-1]

You can then just get the last element of the list. In fact you don't even need to get the date from bash either. Python has time and datetime modules. It would look like this:

import datetime
year = datetime.date.today().year

In the event that you do want to use awk and not some other mechanism this will work (note the removed quotation marks in the second argument):

date = subprocess.Popen(["awk","{print $NF}"],stdin=to_date.stdout)

Tested this on OSX and Fedora.