.TH B3SUM "1" "November 2020" "b3sum 0.3.7" "User Commands"
.SH NAME
b3sum \- compute and check BLAKE3 hash
.SH "USAGE"
.B b3sum
[FLAGS] [OPTIONS] [FILE]...
.SH DESCRIPTION
.PP
Print or check BLAKE3 checksums.
.PP
With no FILE, or when FILE is \-, read standard input.
.SS "FLAGS:"
.TP
\fB\-c\fR, \fB\-\-check\fR
Reads BLAKE3 sums from the [file]s and checks them
.TP
\fB\-h\fR, \fB\-\-help\fR
Prints help information
.TP
\fB\-\-keyed\fR
Uses the keyed mode. The secret key is read from standard
input, and it must be exactly 32 raw bytes.
.TP
\fB\-\-no\-mmap\fR
Disables memory mapping. Currently this also disables
multithreading.
.TP
\fB\-\-no\-names\fR
Omits filenames in the output
.TP
\fB\-\-quiet\fR
Skips printing OK for each successfully verified file.
Must be used with \fB\-\-check\fR.
.TP
\fB\-\-raw\fR
Writes raw output bytes to stdout, rather than hex.
\fB\-\-no\-names\fR is implied. In this case, only a single
input is allowed.
.TP
\fB\-V\fR, \fB\-\-version\fR
Prints version information
.SS "OPTIONS:"
.TP
\fB\-\-derive\-key\fR <CONTEXT>
Uses the key derivation mode, with the given
context string. Cannot be used with \fB\-\-keyed\fR.
.TP
\fB\-l\fR, \fB\-\-length\fR <LEN>
The number of output bytes, prior to hex
encoding (default 32)
.TP
\fB\-\-num\-threads\fR <NUM>
The maximum number of threads to use. By
default, this is the number of logical cores.
If this flag is omitted, or if its value is 0,
RAYON_NUM_THREADS is also respected.
.SS "ARGS:"
.TP
<FILE>...
Files to hash, or checkfiles to check. When no file is given,
or when \- is given, read standard input.
.SH "SEE ALSO"