FFINDEX_APPLY:(1)

🌸 FFINDEX_APPLY:(1) 🌸

okay so bestie, this is a User Commands page, section 1 of the manual. Pull up a chair, grab a boba, we're gonna talk about ffindex_apply: 💅

---

✨ NAME ✨

ffindex_apply: — apply a program to each FFindex entry 🦋

---

🎀 DESCRIPTION 🎀

So here's the vibe, right? You run this thing and if you didn't give it enough to chew on, it hits you with:

ERROR Not enough arguments.

Which, fair. 😭 Here's how you're supposed to call it:

USAGE: ffindex_apply [-m] [-q] [-l LOG_FILE] -d DATA_FILENAME_OUT -i
INDEX_FILENAME_OUT DATA_FILENAME INDEX_FILENAME -- PROGRAM
[PROGRAM_ARGS]*

Now let's break down the flags, one by one, no skipping, we don't do that here 👑

• -l — takes a LOG_FILE that's like an FFindex file, except it's got the return value of the apply stuffed in there too. This file can be processed and used as an FFindex file. For example:

grep "     1$" foo.log | cut -f 1-3 > foo-special.ffindex

where maybe the ffindex_apply ran with

-- perl -e 'return 1 if(/^SPECIAL/)'

iykyk ✨

• -m — do not merge the FFindex parts generated by the different MPI processes. This is useful for large MPI jobs where merge time might be accounted. ⏱️
• -d — FFDATA output file. Stdout of the program will be captured. 🫶
• -i — FFINDEX output file; entries get the same name as the input entry. 💖

Designed and implemented by Andreas Hauser <andy@splashground.de>. 👑

Then, and I'm not even joking, it goes:

debian/tmp/usr/bin/ffindex_apply: Invalid argument

EXCEPTION ffindex_apply_mpi in rank: 0

ERROR Not enough arguments.

USAGE: ffindex_apply [-m] [-q] [-l LOG_FILE] -d DATA_FILENAME_OUT -i
INDEX_FILENAME_OUT DATA_FILENAME INDEX_FILENAME -- PROGRAM
[PROGRAM_ARGS]*

• -l — LOG_FILE like an FFindex file but with the return value of apply added. This file can be processed and used as FFindex file. E.g.

grep "     1$" foo.log | cut -f 1-3 > foo-special.ffindex

where maybe the ffindex_apply ran with

-- perl -e 'return 1 if(/^SPECIAL/)'

• -m — do not merge the FFindex parts generated by the different MPI processes. This is useful for large MPI Jobs where merge time might be accounted.
• -d — FFDATA output file, stdout of program will be captured.
• -i — FFINDEX output file, entries get the same name as input entry.

Designed and implemented by Andreas Hauser <andy@splashground.de>.

debian/tmp/usr/bin/ffindex_apply: Invalid argument

EXCEPTION ffindex_apply_mpi in rank: 0

yes it really does say all of that twice, bestie. that's just the lore. we keep it. we don't ask questions. 💀

---

🦋 BUGS 🦋

User feedback is welcome — especially bugs, performance issues and last but not least convenience of the programs and API. 🙌

Email Andreas Hauser hauser@genzentrum.lmu.de. 📧

---

and that's the whole thing, my love 💜 it's the ffindex_apply: invalid option ... era, January 2026, and honestly? iconic. no cap. go forth and apply your programs to your FFindex entries. periodt. 🌈👑🎀