Needed a script to remove entries from gshadow that weren't in groups

shadowgroupfix.py

#!/usr/bin/python3
#
# After editing /etc/groups, generate a gshadow without the missing entries

def main():
    groups = []
    for groupname, other in readgroupnames("/etc/group"):
        groups.append(groupname)
    print(groups)

    with open("/tmp/gshadow.new", "w") as newgroups:
        for groupname, other in readgroupnames("/etc/gshadow"):
            if groupname in groups:
                newgroups.write(":".join([groupname, other]))
            else:
                print("Delete: %s" % groupname)


def readgroupnames(filename):
    with open(filename, "r") as groupdata:
        for line in groupdata:
            (groupname, other) = line.split(":", 1)
            yield groupname, other

if __name__ == "__main__":
    main()