copyfilerange1
Copy range(s) from source to destination file
Usage
copyfilerange [options]
source
destination
range ...
Overview
The copyfilerange command copies byte ranges from source to destination file. It is a wrapper around the copy_file_range(2) system call.
The command can be used to create files with unallocated gaps (sparse files) and/or with shared blocks between multiple files (reflinks).
Each range is of the form source_offset:destination_offset:length, with all values in bytes. If length is 0, then as much data as is available is copied. Multiple ranges may be supplied.
When one or both of the offsets are omitted, the operation uses the last-used file location, starting with 0.
Options
-
-r, --ranges file -
Read range(s) separated by newlines from this file.
-
-v, --verbose -
Verbose output of the copied ranges.
-
-h, --help -
Display help text and exit.
-
-V, --version -
Display version and exit.
Exit status
0
success
1
unspecified failure
Notes
The copy_file_range(2) system call has some serious caveats: the source and destination files must use the same filesystem type, and some virtual filesystems (like procfs) won’t work. copy_file_range(2) will use reflinks when the filesystem supports this. To use reflinks, the file range most often needs to align with the filesystem block size on both the source and destination file.
Examples
copyfilerange original-file reflink ::
copyfilerange original-file first-block ::4096
copyfilerange original-file even-blocks -r <(seq 0 8192 40960|awk '{print $1"::4096"}')
copyfilerange original-file sparse-file 0:1M:1
copyfilerange original-file split-first-mb ::1M
copyfilerange original-file split-remainder 1M::
copyfilerange split-first-mb join ::
copyfilerange split-remainder join :1M: