zeroUtility.py

import os
import pwd

def linePrepender(filename, line):
    with open(filename, 'r+') as f:
        content = f.read()
        if content.split('\n')[0] == line:
            return
        f.seek(0, 0)
        f.write(line.rstrip('\r\n') + '\n' + content)

def lineSubstitutor(filename, line1, line2):
    with open(filename, 'r+') as f:
        content = f.read().split(line1)
        f.seek(0, 0)
        f.write(content[0] + line2.rstrip('\r\n') + '\n' + content[1])


def changeUser(user):
     pwRecord = pwd.getpwnam(user)
     env = os.environ.copy()
     env['HOME'] = pwRecord.pw_dir
     env['LOGNAME'] = pwRecord.pw_name
     env['PWD'] = pwRecord.pw_dir
     env['USER'] = user
     def demote(userUid, userGid):
         def seyIds():
             os.setgid(userGid)
             os.setuid(userUid)
         return set_ids
     return env, pwRecord

def demote(userUid, userGid):
     def setIds():
         os.setgid(userGid)
         os.setuid(userUid)
     return setIds