SAVECORE(8)

✨ SAVECORE(8) ✨

okay so bestie, buckle up — this is savecore, section 8 of the System Manager's Manual, and it's literally the girl who saves your crash for later 💾✨

💖 NAME 💖

savecore — save a core dump of the operating system 🫶

---

🎀 SYNOPSIS 🎀

savecore -c [-v] [device ...]
savecore -C [-v] [device ...]
savecore -L [-fvZz] [-m maxdumps] [directory]
savecore [--libxo] [-fkuvz] [-m maxdumps] [directory [device ...]]

🌸 DESCRIPTION 🌸

The savecore utility copies a core dump into directory, or into the current working directory if you didn't hand it a directory argument, and then it enters a reboot message plus info about the core dump into the system log. it's giving "i'm saving this for the group chat" energy honestly 💅

The options are as follows:

• --libxo — generate output via libxo(3) in a selection of different human and machine readable formats ✨. see xo_options(7) for details on command line arguments.
• -C — check to see if a dump exists, and display a brief message to indicate the status. an exit status of 0 indicates that a dump is there, 1 indicates that none exists. this option is compatible only with the [-v] option.
• -c — clear the dump, so that future invocations of savecore will ignore it. bye bestie 👋
• -f — force a dump to be taken even if either the dump was cleared or if the dump header information is inconsistent. it's giving pushy but make it necessary 💪
• -k — do not clear the dump after saving it. keep it, queen 👑
• -L — instruct savecore to generate and save a kernel dump of the running system, rather than copying one from a dump device.
• -m maxdumps — maximum number of dumps to store. once the number of stored dumps is equal to maxdumps the counter will restart from 0. the circle of life 🦋
• -u — uncompress the dump in case it was compressed by the kernel.
• -v — print out some additional debugging information. specify twice for more information (yes, twice. she's chatty 😭).
• -Z — compress the dump (see zstd(1)). this option is only supported in conjunction with the -L option. regular dumps can be configured for compression with zstd using dumpon(8).
• -z — compress the dump (see gzip(1)). the dump may already be compressed if the kernel was configured to do so by dumpon(8). in this case, the option has no effect. like, nothing. zero. nada 🙈

if used in conjunction with the -L option, the requested live dump will be compressed with gzip.

The savecore utility looks for dumps on each device specified by the device argument(s), or on each device in /etc/fstab marked as “dump” or “swap”. 🔍

The savecore utility checks the core dump in various ways to make sure that it is complete. vibe check, basically. if it passes these checks, it saves the core image in directory/vmcore.# and information about the core in directory/info.#. if the core is encrypted, it saves the dump key in directory/key.# 🔑. the core can be later decrypted using decryptcore(8). for kernel textdumps generated with the textdump(4) facility, output will be stored in the tar(5) format and named directory/textdump.tar.#.

the “#” is the number from the first line of the file directory/bounds, and it is incremented and stored back into the file each time savecore successfully runs. so it's always counting up, main character energy fr fr 🔥

The savecore utility also checks the available disk space before attempting to make the copies. if there is insufficient disk space in the file system containing directory, or if the file directory/minfree exists and the number of free kilobytes (for non-superusers) in the file system after the copies were made would be less than the number in the first line of this file, the copies are not attempted. no space, no save, sorry babe 😔

If savecore successfully copies the kernel and the core dump, the core dump is cleared so that future invocations of savecore will ignore it.

ngl the whole point of this utility is that it's meant to be called near the end of the initialization file /etc/rc (see rc(8)). that's her whole gig 💅

---

🦋 SEE ALSO 🦋

gzip(1), zstd(1), getbootfile(3), libxo(3), xo_options(7), mem(4), textdump(4), tar(5), crashinfo(8), decryptcore(8), dumpon(8), syslogd(8)

⭐ HISTORY ⭐

The savecore utility appeared in 4.1BSD — she's an icon, she's a legend, and she is the moment ✨

Support for kernel textdumps appeared in FreeBSD 7.1.

💀 BUGS 💀

The minfree code does not consider the effect of compression or sparse files. yeah… she's not perfect, but we love her anyway 🥺

---

🌷 okay that's the whole page bestie! this came from the Debian build, dated July 16, 2025, SAVECORE(8) — mwah, go save some cores 💖🎀🫶