write and Replace particular line in file

Question

I want to replace value of key(i.e db_host, addons_path) with $$$$.

Input text file contains the following:

#         


        

Answer 1

If you want to do that with Python, you can use the following function:

def replace_in_file(filename, key, new_value):
    f = open(filename, "r")
    lines = f.readlines()
    f.close()
    for i, line in enumerate(lines):
        if line.split('=')[0].strip(' \n') == key:
            lines[i] = key + ' = ' + new_value + '\n'
    f = open(filename, "w")
    f.write("".join(lines))
    f.close()

replace_in_file("file.txt", 'db_host', "7777")