FCRONDYN(1)

📦
version 3.4.1 · 2 versions
, in arch rolling, nixpkgs unstable

🦋 FCRONDYN(1) — the fcrondyn page, bestie edition 🦋

okay so this is fcrondyn from the fcron manual, and I'm gonna walk you through literally every single thing on the page because you deserve to know it all 💅

✨ NAME ✨

fcrondyn — dialog dyn-amically with a running fcron daemon 🫶

(yes the original says "dyn-amically", it's iconic, we're keeping it, no notes)

✨ SYNOPSIS ✨

fcrondyn [ -c file ] [ -i ]

fcrondyn [ -c file ] -x command

fcrondyn [ -h ]

three whole moods, pick your fighter 💖

✨ DESCRIPTION ✨

So Fcrondyn is a user tool that's built to interact with a running fcron daemon — like, the two of them are in a group chat and fcrondyn is the one texting 🌸

What can it do? For instance: list user's jobs loaded by fcron, run one of them, renice a running job, send a signal to a running job, etc. It's giving personal assistant to your crontab, honestly 👑

✨ OPTIONS ✨

  • -i — run fcrondyn in interactive mode. Also lowkey, fcrondyn is run in interactive mode when no option is given at all — so if you just vibe and hit enter, that's interactive too ✨
  • -x command — run command and returns immediately. See below for syntax and a list of commands.
Note: If the command string consists of multiple words or contains spaces, you must enclose it in quotes in your shell. fr fr, don't forget the quotes or it'll get messy 🙈
  • -c file — make fcrondyn use config file file instead of default config file /usr/local/etc/fcron.conf. To interact with a running fcron process, fcrondyn must use the same config file as the process. That way, several fcron processes can run simultaneously on a single system 👯‍♀️ (they don't have to fight, they can coexist)
  • -d — run in debug mode. In this mode, many informational messages will be output in order to check if anything went wrong 🕵️‍♀️
  • -h — display a brief description of the options.
  • -V — display an informational message about fcrondyn, including its version and the license under which it is distributed 📜

💜 COMMAND DESCRIPTION 💜

Fcrondyn's command syntax is the following:

command arg1 arg2 [...]

An argument of a fcrondyn command is of one of the following type — welcome to "ARGUMENT TYPES OF FCRONDYN'S COMMANDS" 🎀

  • user — a valid user name.
  • jobid — a job id given by one of fcrondyn's ls* commands (i.e. an integer).
  • sig — a signal number, or its name (case does not matter). For instance, "term" or "15".
  • niceval — a job priority value. A niceval is an integer from -20 (highest priority) to 19 (lowest) (only root is allowed to use a negative value with this option).

Last, but not least, the following commands are recognized (optional arguments are between []) — presenting "VALID FCRONDYN'S COMMANDS" ⭐

  • help
  • h — print an help message about fcrondyn's commands.
  • quit
  • q — in interactive mode, quit fcrondyn.
  • ls [user] — list all jobs of user. When ls is run by root, all users are listed unless a user name is given as argument. See below for some explanations about the fields used by ls* commands.
  • ls_lavgq [user] — same as ls, but list only the jobs which are in the load-average queue (i.e. which are waiting for a lower load average to be run) 😴
  • ls_serialq [user] — same as ls, but list only the jobs which are in the serial queue (i.e. which are waiting for other jobs to be finished).
  • ls_exeq [user] — same as ls, but list only the jobs which are running. main character energy 🏃‍♀️
  • detail jobid — print details about a job. jobid is the one given by ls.
  • runnow jobid — instead of waiting for the next scheduled execution time, run the job now. The next execution time is changed as if the job had run on schedule. ⏰
  • run jobid — run the job now. Its next execution time is not changed. (different from runnow, do not mix them up bestie 💀)
  • kill sig jobid — send a signal to a running job.
  • renice niceval jobid — change the priority of a running job.

🌸 FIELDS USED BY DETAIL AND LS* COMMANDS 🌸

  • ID — job's unique identification number.
  • USER — user who owns this job.
  • PID — the pid of the running job.
  • INDEX — index of the job in the serial queue (i.e. it will be run when all the jobs of an inferior index have been run).
  • R&Q — the job has this number instances of the given task which are either running or queued in the serial or lavg queue.

✨ OPTIONS ✨

List of main options which are set for the task:

  • L — job which runs only under a given system Load average (option lavg, lavg1, lavg5, and lavg15).
  • LO — Load average Once — if only at most one instance of the task can be in the load average queue at a given time (option lavgonce).
  • S — for serialized jobs (option serial).
  • ST — Serial Temporary — For the jobs which will be serialized only for the next execution (e.g. because of bootrun).
  • SO — Serial Once — if only at most one instance of the task can be in the serial queue at a given time (option serialonce).
  • ES — if several instances of the same job can run simultaneously (option exesev).

🧚 the rest of the fields 🧚

  • LAVG — 3 values, corresponding to the 1, 5, and 15-minute (in this order) system load average values below which the job will be run, otherwise it will be queued until the system load average is appropriate (see lavg option).
  • UNTIL — field corresponding to the until option.
  • STRICT — field corresponding to the strict option. Y for yes, N for no.
  • SCHEDULE — next run is scheduled at this time and date. Please note that fcrondyn prints the next execution time and date in the time zone of the system where fcron is running, and not the time zone which can be defined for using option timezone. ⚠️ timezone plot twist
  • CMD — the command that will be executed.

🎀 RETURN VALUES 🎀

Fcrondyn returns 0 on normal exit and 1 on error. slay when it's 0 💖

🎀 CONFORMING TO 🎀

Should be POSIX compliant. ✨

🎀 FILES 🎀

  • /usr/local/etc/fcron.conf — configuration file for fcron, fcrontab and fcrondyn: contains paths (spool dir, pid file) and default programs to use (editor, shell, etc). See fcron.conf(5) for more details.
  • /usr/local/etc/fcron.allow — users allowed to use fcrontab and fcrondyn (one name per line, special name "all" acts for everyone).
  • /usr/local/etc/fcron.deny — users who are not allowed to use fcrontab and fcrondyn (same format as allow file).
  • /usr/local/etc/pam.d/fcron (or /usr/local/etc/pam.conf) — PAM configuration file for fcron. Take a look at pam(8) for more details. 🔐

👑 SEE ALSO 👑

If you're learning how to use fcron from scratch, I suggest that you read the HTML version of the documentation (if your are not reading it right now! :)) — the content is the same, but it is easier to navigate thanks to the hyperlinks. 🦋

💜 AUTHOR 💜

Thibault Godouet <fcron@free.fr> 💌

okay and the sign-off: this page is from fcron, dated 06/06/2026 (aka 06 June 2026), and it's the FCRONDYN(1) page — ily, go renice something responsibly 🌈✨💅

📦 where this page comes from