run perl command in python file

Question

import subprocess
result=subprocess.Popen(['perl','Hello.pl'],stdout=subprocess.PIPE,shell=True)
out,err=result.communicate()
print out

This is my program , i am trying to run a perl program inside a python file . I am using python 2.6v .

While running this file it's not giving anything .

I am new to python .

Can anyone help ?

Answer 1

From this documentation for communicate():

Interact with process: Send data to stdin. Read data from stdout and stderr, until end-of-file is reached. Wait for process to terminate.

Don't use shell=True, if you want to write and read without waiting for the process to stop. Refer this doc for details.

Use this code:

import subprocess
result=subprocess.Popen(['perl','Hello.pl'],stdout=subprocess.PIPE)
out,err=result.communicate()
print out

How can i read some arguments from command line and pass as an input . For Ex : perl Hello.pl some_variable_name

You can do that using argparse

Python code:

import subprocess
import argparse

parser = argparse.ArgumentParser(description='Test Python Code')
parser.add_argument('first_name', metavar='FIRST_NAME', type=str,
                    help='Enter the first name')
parser.add_argument('second_name', metavar='SECOND_NAME', type=str,
                    help='Enter the second name')

# Parse command line arguments
args = parser.parse_args()

result=subprocess.Popen(['perl','Hello.pl',args.first_name,args.second_name],stdout=subprocess.PIPE)
out,err=result.communicate()
print out

Perl Code:

#!/usr/bin/perl -w

# (1) quit unless we have the correct number of command-line args
$num_args = $#ARGV + 1;
if ($num_args != 2) {
    print "\nUsage: name.pl first_name last_name\n";
    exit;
}

# (2) we got two command line args, so assume they are the
# first name and last name
$first_name=$ARGV[0];
$last_name=$ARGV[1];

print "First name: $first_name \nSecond name: $last_name\n";

Sample output: