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'\" t
.\" Title: bits
.\" Author: [see the "AUTHOR(S)" section]
.\" Generator: Asciidoctor 2.0.20
.\" Date: 2026-02-17
.\" Manual: User Commands
.\" Source: util-linux 2.42-rc1
.\" Language: English
.\"
.TH "BITS" "1" "2026-02-17" "util\-linux 2.42\-rc1" "User Commands"
.ie \n(.g .ds Aq \(aq
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.\}
.SH "NAME"
bits \- convert bit masks or lists from/to various formats
.SH "SYNOPSIS"
.sp
\fBbits\fP [\fB\-h\fP] [\fB\-V\fP] [\fB\-w\fP \fInumber\fP] [\fImode\fP] [\fImask\fP|\fIlist\fP]...
.SH "DESCRIPTION"
.sp
The \fBbits\fP utility converts between bit masks and bit lists.
It supports combining multiple masks or lists using bitwise operations.
.SH "POSITIONAL ARGUMENTS"
.sp
\fImask\fP
.RS 4
A set of bits specified as a hexadecimal mask value
(for example: \fB0xeec2\fP).
.RE
.sp
\fIlist\fP
.RS 4
A set of bits specified as a comma\-separated list of bit IDs
(for example: \fB1,5,29,32\fP).
.RE
.sp
If no argument is specified, the sets of bits will be read from
standard input, one group per line.
.sp
Consecutive IDs can be compressed as ranges
(for example: \fB5,6,7,8,9,10\fP \(-> \fB5\-10\fP).
.sp
Optionally, if an argument starts with a comma, it will be
parsed as a single hexadecimal mask split in 32\-bit groups
(for example: \fB,00014000,00000000,00020000\fP \(-> \fB17,78,80\fP).
.sp
By default, all groups will be OR\(cqed together. If a group has one of
the prefixes \fB&\fP, \fB^\fP, or \fB~\fP, it will be combined with the
resulting mask using a different binary operation:
.sp
\fB&\fP\fImask\fP|\fB&\fP\fIlist\fP
.RS 4
The group will be combined with a binary AND operation.
That is: all bits that are set to 1 in the group AND in the combined groups
so far will be preserved as 1. All other bits will be reset to 0.
.RE
.sp
\fB^\fP\fImask\fP|\fB^\fP\fIlist\fP
.RS 4
The group will be combined with a binary XOR operation.
That is: all bits that are set to 1 in the group AND to 0 in the combined
groups so far (or the other way around) will be set to 1.
Bits that are set both to 1 or both to 0 will be reset to 0.
.RE
.sp
\fB~\fP\fImask\fP|\fB~\fP\fIlist\fP
.RS 4
All bits set to 1 in the group will be cleared (reset to 0) in the combined
groups so far.
.RE
.SH "OPTIONS"
.sp
\fB\-w\fP \fInumber\fP, \fB\-\-width\fP \fInumber\fP
.RS 4
The maximum number of bits in the masks handled by \fBbits\fP.
The default is \fB8192\fP. Any bit larger than this number will be truncated.
.RE
.sp
\fB\-h\fP, \fB\-\-help\fP
.RS 4
Display help text and exit.
.RE
.sp
\fB\-V\fP, \fB\-\-version\fP
.RS 4
Display version and exit.
.RE
.SH "CONVERSION MODE"
.sp
One of the following conversion modes can be specified. If not specified, it
defaults to \fB\-m\fP, \fB\-\-mask\fP.
.sp
\fB\-b\fP, \fB\-\-binary\fP
.RS 4
Print the combined arguments as a binary mask value.
.RE
.sp
\fB\-g\fP, \fB\-\-grouped\-mask\fP
.RS 4
Print the combined arguments as a hexadecimal mask value
in 32\-bit comma\-separated groups.
.RE
.sp
\fB\-l\fP, \fB\-\-list\fP
.RS 4
Print the combined arguments as a list of bit IDs.
Consecutive IDs are compressed to ranges.
.RE
.sp
\fB\-m\fP, \fB\-\-mask\fP
.RS 4
Print the combined arguments as a hexadecimal mask value (default).
.RE
.SH "EXAMPLES"
.sp
.if n .RS 4
.nf
.fam C
~$ bits \-\-mask 4,5\-8 16,30
0x400101f0
~$ bits \-\-list 0xeec2
1,6,7,9\-11,13\-15
~$ bits \-\-binary 4,5\-8 16,30
0b100_0000_0000_0001_0000_0001_1111_0000
~$ bits \-\-list ,00300000,03000000,30000003
0,1,28,29,56,57,84,85
~$ bits \-\-list 1,2,3,4 ~3\-10
1,2
~$ bits \-\-list 1,2,3,4 ^3\-10
1,2,5\-10
~$ bits \-\-grouped\-mask 2,22,74,79
8400,00000000,00400004
~$ bits \-\-width 64 \-\-list 2,22,74,79
2,22
.fam
.fi
.if n .RE
.SH "AUTHORS"
.sp
Robin Jarry.
.SH "REPORTING BUGS"
.sp
For bug reports, use the \c
.URL "https://github.com/util\-linux/util\-linux/issues" "issue tracker" "."
.SH "AVAILABILITY"
.sp
The \fBbits\fP command is part of the util\-linux package which can be downloaded from \c
.URL "https://www.kernel.org/pub/linux/utils/util\-linux/" "Linux Kernel Archive" "."
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