compare.py

oldfile = open('freeze_old.txt')
newfile = open('freeze_new.txt')

packages = {}

def splitpackage(line):
    result = line.split('==')
    if not len(result) == 2:
        result = line.split('@')
        
        if not len(result) == 2:
            raise Exception('Weird result of splitting: %s' % result)
    
    return map(lambda x: x.strip(), result)

for line in oldfile.readlines():
    package, version = splitpackage(line)
    print 'Added %s (%s)' % (package, version)
    packages[package] = version

print
print 'Result:'

for line in newfile.readlines():
    package, version = splitpackage(line)
    
    if package in packages:
        old_version = packages[package]
        if version != old_version:
            print '%s - Old: %s New: %s' % (package, old_version, version)