Re: why does open ">..." sometimes touches the directory?

[sundialsvc4]

Probably the safest assumption is simply to assume that “it might.”   Actual behavior can depend on the OS-type and, within Unix/Linux, exactly what filesystem is used and how that filesystem is configured.   All of which is really beyond your control.   So, don&rquo;t get upset if the mod-time of a directory changes, and, don’t use mod-time as a sentinel to tell you whether or not you need to dumpster-dive into a particular directory.