using variable in a url in python

You need to pass the actual variable, you can iterate over the file object so you don't need to use readlines and use with to open your files as it will close them automatically. You also need the print inside the loop if you want to see each line and str.rstrip() will remove any newlines from the end of each line:

with open('/home/list.txt') as f:  
    for ip in f:
        print "https://{0}/result".format(ip.rstrip())

If you want to store all the links use a list comprehension:

with  open('/home/list.txt' as f:
    links = ["https://{0}/result".format(ip.rstrip()) for line in f]

For python 2.6 you have to pass the numeric index of a positional argument, i.e {0} using str.format .

You can also use names to pass to str.format:

with open('/home/list.txt') as f:
    for ip in f:
        print "https://{ip}/result".format(ip=ip.rstrip())

Get the link inside the loop, you are not appending data to it, you are assigning to it every time. Use something like this:

file = open('/home/list.txt', 'r')

for line in file.readlines():
    source = line.strip('\n')
    print source
    link = "https://%s/result" %(source)
    print link

Try this:

lines = [line.strip('\n') for line in file]

for source in lines:
    print source

for source in lines:
    link = "https://{}/result".format(source)
    print link

The feature you just described is often called string interpolation. In Python, this is called string formatting.

There are two styles of string formatting in Python: the old style and the new style. What I've shown in the example above is the new style, in which we format with a string method named format. While the old style uses the % operator, eg. "https://%s/result" % source

Use format specifier for string and also put the link printing section in the for loop only something like this:

import sys
import os
    file = open('/home/list.txt', 'r')
    for line in file.readlines():
        source = line.strip('\n')
        print source
        link = "https://%s/result”%source
        print link

import sys
import os

file = open('/home/list.txt', 'r')

for line in file.readlines():
    source = line.strip('\n')
    print source
    link = "https://" + str(source) + "/result”
    print link