Scheduling (Task Scheduler, launchd, cron)

Older but useful explanation of launchd replacing cron on the Mac, the five folders where launch plists live, and the difference that agents can interact with the user session while daemons cannot. Suggests checking for legacy crontabs and mentions the Lingon X editor.

Security-focused look at the LaunchAgents and LaunchDaemons folders: where they are, which are SIP-protected under /System/Library and which are not, and why malware uses them to persist. Useful for knowing which launch folders to audit.

VikingOSX shows a working LaunchAgent for a shell script: plist in ~/Library/LaunchAgents with 644 permissions, Label, RunAtLoad, StartInterval and full paths only. The original poster got theirs working after moving the script out of ~/Documents, and etresoft points to privacy permissions instead, noting shell scripts silently fail without Full Disk Access.

A script that worked by hand failed under Task Scheduler. The accepted answer says not to tick Do not store password when using Run whether user is logged on or not, since the task then cannot reach network resources, and to isolate the problem with a trivial test script and -noexit. Rich Matheisen recommends Start-Transcript for diagnosis and says two-factor authentication won't work in a scheduled task; the poster suspected a smart-card PIN prompt. No confirmed final fix is recorded.

Compares Login Items with LaunchAgents and LaunchDaemons: global ones in /Library load before any user logs in, per-user ones after login, and daemons have no window server access. The author favours launchd for background services and Login Items for apps with a UI.

Explains that launchd, driven by launchctl and property list files in the LaunchAgents and LaunchDaemons folders, is the macOS way to run things automatically, with cron deprecated. Key plist keys: ProgramArguments, RunAtLoad and StartInterval (seconds).

Accepted self-answer: a LaunchAgent loaded for one user would not run for a second user because its stdout/stderr log file in /tmp had been created with mode 0644 on the first run and was not writable by others. Pre-creating the file with chmod a+rw and reloading the agent fixed it. Pointing logs to a per-user location is a safer alternative.

Reference for launchctl including the modern bootstrap and bootout subcommands, which replace the legacy load and unload and generally avoid sudo for user agents. Shows print, bootstrap gui/<uid> and bootout examples.

Reference for creating a Windows scheduled task from PowerShell by combining New-ScheduledTaskAction and New-ScheduledTaskTrigger with Register-ScheduledTask. It lists parameter limits (up to 32 actions and 48 triggers) and the Principal and RunLevel options for choosing the account and privilege level.

The manual page for systemd timer units: OnCalendar for wall-clock schedules, Persistent= to run missed jobs after downtime, RandomizedDelaySec and AccuracySec. A timer activates the same-named .service by default.

A 2015 thread with practical launchd debugging: a replier found that using ~ in ProgramArguments stopped the agent from starting while a full path worked, that the path should point at the executable inside the bundle, and the thread shows inspecting state with launchctl list, print and blame. Aimed at XPC agents, and the home-directory problem never got a firm root cause.