effective user ID
In Unix-like operating systems, the user ID used for permission checks, which may differ from the real user ID when a setuid program is executed.
To check the effective user ID of a process, use a dedicated function.
Real user ID identifies the user who started the process, while effective user ID determines actual permissions.
Compound of 実効 (effective) + 利用者 (user) + ＩＤ (ID), a direct translation of the English computing term 'effective user ID'.