sync - Man Page

• Flush all pending write operations on all disks: sync
• Flush all pending write operations on a single file to disk: sync path/to/file
• Flush writes and drop filesystem caches: sync; echo 3 | sudo tee /proc/sys/vm/drop_caches

tldr.sh

sync [OPTION] [FILE]...

Synchronize cached writes to persistent storage

If one or more files are specified, sync only them, or their containing file systems.

-d,  --data

sync only file data, no unneeded metadata

-f,  --file-system

sync the file systems that contain the files

--help

display this help and exit

--version

output version information and exit

Persistence guarantees vary per system. See the system calls below for more details.

Written by Jim Meyering and Giuseppe Scrivano.

Report bugs to: <bug-coreutils@gnu.org>.
Report any translation bugs to: <https://translationproject.org/team/>.
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>

Copyright © 2026 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

fdatasync(2), fsync(2), sync(2), syncfs(2)

Full documentation <https://www.gnu.org/software/coreutils/sync>
or available locally via: info '(coreutils) sync invocation'