Error with python string formatting

Question

I am working on a script that takes a text file containing IP addresses (one per line) and then passes each IP into a non-Python program command.

The result is an error:

TypeError: not all arguments converted during string formatting

import subprocess
list='c:\cmc_list.txt'
with open(list,'r') as cmc_list:
for i in cmc_list:
 racadm_command = "racadm -r %s -u root -p calvin getslotname" % i
output = subprocess.Popen(racadm_command % i, stdout = subprocess.PIPE, 
 shell=True).communicate()[0]
print(racadm_command, output)

• sacuL: Welcome to SO! Please be sure to post properly indented code, especially for python questions, where indentation matters.
• Eric: What are the values in the text file? Has the file run properly in the past? Were there any edits since?
• OneCricketeer: What is racadm_command % i supposed to do that isn't already done?
• Jon: I'm with @cricket_007. I don't think the extra % i is needed after racadm_command.
• OneCricketeer: By the way, you should avoid naming variables as list or any other Python data type

Answer 1

The string passed to the Popen command has already been formatted, so it has no % left to consume the i. Take away the "% i" and I think you'll be fine.

• Smith: Thank you. Removing the % i from Popen allowed the script to run.

Answer 2

I believe you meant to do the formatting only once

import subprocess
cmc_list='c:\cmc_list.txt'
racadm_command_template = "racadm -r {} -u root -p calvin getslotname"
with open(cmc_list,'r') as f:
 for ip in f:
 cmd = racadm_command_template.format(ip)
 output = subprocess.Popen(cmd, stdout = subprocess.PIPE, shell=True).communicate()
 print(cmd, output[0])

I also suggest using getpass for your password prompt, or import from an environment variable. Additionally, don't print out the password and please change it from the default

• Smith: Thank you. Your version of the script runs successfully. This is my first python script. Its purely educational so password handling was not a priority but I do appreciate the tip. I'm assuming you are familiar with the targets here since you know its the default password. I'm curious about your choices to replace cmc_list with f and i with ip; also moving the [0] from the output definition to the print function.Why those choices?
• Smith: Upon further inspection. For every IP in the list with the exception of the last it executes the command prematurely; so what should be "racadm -r %s -u root -p calvin getslotname" winds up being "racadm -r %s" on all but last IP in list. Thoughts?
• OneCricketeer: i is commonly used as a numeric iterator, not a line in a file, while f is a "file object". Variable names aren't too important otherwise, but list is a builtin Python type, so you wouldn't have been able to use the list() function otherwise. I moved the [0] so you could also access the other values of the output, if needed. Regarding the final line, I'm not using %s here, but I don't think that should happen
• Smith: please see above
• OneCricketeer: Please post a new question rather than edit one you already accepted.