What is the 'bs' option in dd?
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I've found conflicting information on the internet on whether the bs in a command like dd bs=512 if=/home/Downloads/ubuntu.iso of=/dev/sdb stands for "bytes per second" or "block size". I couldn't find anything in the man pages, as the only reference to bs is:
bs=BYTES
read and write up to BYTES bytes at a time
dd
asked Apr 3 at 12:54
NerdOfLinux
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up vote
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I've found conflicting information on the internet on whether the bs in a command like dd bs=512 if=/home/Downloads/ubuntu.iso of=/dev/sdb stands for "bytes per second" or "block size". I couldn't find anything in the man pages, as the only reference to bs is:
bs=BYTES
read and write up to BYTES bytes at a time
dd
asked Apr 3 at 12:54
NerdOfLinux
1,499830
512 Bytes per second would be painfully slow
– RoVo
Apr 3 at 13:01
I know, that was just the first number that popped into my head while writing that
– NerdOfLinux
Apr 3 at 13:02
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I've found conflicting information on the internet on whether the bs in a command like dd bs=512 if=/home/Downloads/ubuntu.iso of=/dev/sdb stands for "bytes per second" or "block size". I couldn't find anything in the man pages, as the only reference to bs is:
bs=BYTES
read and write up to BYTES bytes at a time
dd
asked Apr 3 at 12:54
NerdOfLinux
1,499830
I've found conflicting information on the internet on whether the bs in a command like dd bs=512 if=/home/Downloads/ubuntu.iso of=/dev/sdb stands for "bytes per second" or "block size". I couldn't find anything in the man pages, as the only reference to bs is:
bs=BYTES
read and write up to BYTES bytes at a time
dd
dd
asked Apr 3 at 12:54
NerdOfLinux
1,499830
asked Apr 3 at 12:54
NerdOfLinux
1,499830
asked Apr 3 at 12:54
NerdOfLinux
1,499830
asked Apr 3 at 12:54
NerdOfLinux
1,499830
asked Apr 3 at 12:54
NerdOfLinux
1,499830
1,499830
512 Bytes per second would be painfully slow
– RoVo
Apr 3 at 13:01
I know, that was just the first number that popped into my head while writing that
– NerdOfLinux
Apr 3 at 13:02
add a comment |Â
512 Bytes per second would be painfully slow
– RoVo
Apr 3 at 13:01
I know, that was just the first number that popped into my head while writing that
– NerdOfLinux
Apr 3 at 13:02
512 Bytes per second would be painfully slow
– RoVo
Apr 3 at 13:01
512 Bytes per second would be painfully slow
– RoVo
Apr 3 at 13:01
I know, that was just the first number that popped into my head while writing that
– NerdOfLinux
Apr 3 at 13:02
I know, that was just the first number that popped into my head while writing that
– NerdOfLinux
Apr 3 at 13:02
add a comment |Â
1 Answer
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up vote
3
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As with other GNU Coreutils utilities, the primary documentation is the info page.
From info coreutils dd invocation :
‘bs=BYTES’
Set both input and output block sizes to BYTES. This makes ‘dd’
read and write BYTES per block, overriding any ‘ibs’ and ‘obs’
settings. In addition, if no data-transforming ‘conv’ option is
specified, input is copied to the output as soon as it’s read, even
if it is smaller than the block size.
There are corresponding parameters for the individual read, write and conversion block sizes:
‘ibs=BYTES’
Set the input block size to BYTES. This makes ‘dd’ read BYTES per
block. The default is 512 bytes.
‘obs=BYTES’
Set the output block size to BYTES. This makes ‘dd’ write BYTES
per block. The default is 512 bytes.
‘cbs=BYTES’
Set the conversion block size to BYTES. When converting
variable-length records to fixed-length ones (‘conv=block’) or the
reverse (‘conv=unblock’), use BYTES as the fixed record length.
answered Apr 3 at 13:00
steeldriver
63k1198166
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
As with other GNU Coreutils utilities, the primary documentation is the info page.
From info coreutils dd invocation :
‘bs=BYTES’
Set both input and output block sizes to BYTES. This makes ‘dd’
read and write BYTES per block, overriding any ‘ibs’ and ‘obs’
settings. In addition, if no data-transforming ‘conv’ option is
specified, input is copied to the output as soon as it’s read, even
if it is smaller than the block size.
There are corresponding parameters for the individual read, write and conversion block sizes:
‘ibs=BYTES’
Set the input block size to BYTES. This makes ‘dd’ read BYTES per
block. The default is 512 bytes.
‘obs=BYTES’
Set the output block size to BYTES. This makes ‘dd’ write BYTES
per block. The default is 512 bytes.
‘cbs=BYTES’
Set the conversion block size to BYTES. When converting
variable-length records to fixed-length ones (‘conv=block’) or the
reverse (‘conv=unblock’), use BYTES as the fixed record length.
answered Apr 3 at 13:00
steeldriver
63k1198166
add a comment |Â
up vote
3
down vote
accepted
As with other GNU Coreutils utilities, the primary documentation is the info page.
From info coreutils dd invocation :
‘bs=BYTES’
Set both input and output block sizes to BYTES. This makes ‘dd’
read and write BYTES per block, overriding any ‘ibs’ and ‘obs’
settings. In addition, if no data-transforming ‘conv’ option is
specified, input is copied to the output as soon as it’s read, even
if it is smaller than the block size.
There are corresponding parameters for the individual read, write and conversion block sizes:
‘ibs=BYTES’
Set the input block size to BYTES. This makes ‘dd’ read BYTES per
block. The default is 512 bytes.
‘obs=BYTES’
Set the output block size to BYTES. This makes ‘dd’ write BYTES
per block. The default is 512 bytes.
‘cbs=BYTES’
Set the conversion block size to BYTES. When converting
variable-length records to fixed-length ones (‘conv=block’) or the
reverse (‘conv=unblock’), use BYTES as the fixed record length.
answered Apr 3 at 13:00
steeldriver
63k1198166
add a comment |Â
up vote
3
down vote
accepted
up vote
3
down vote
accepted
As with other GNU Coreutils utilities, the primary documentation is the info page.
From info coreutils dd invocation :
‘bs=BYTES’
Set both input and output block sizes to BYTES. This makes ‘dd’
read and write BYTES per block, overriding any ‘ibs’ and ‘obs’
settings. In addition, if no data-transforming ‘conv’ option is
specified, input is copied to the output as soon as it’s read, even
if it is smaller than the block size.
There are corresponding parameters for the individual read, write and conversion block sizes:
‘ibs=BYTES’
Set the input block size to BYTES. This makes ‘dd’ read BYTES per
block. The default is 512 bytes.
‘obs=BYTES’
Set the output block size to BYTES. This makes ‘dd’ write BYTES
per block. The default is 512 bytes.
‘cbs=BYTES’
Set the conversion block size to BYTES. When converting
variable-length records to fixed-length ones (‘conv=block’) or the
reverse (‘conv=unblock’), use BYTES as the fixed record length.
answered Apr 3 at 13:00
steeldriver
63k1198166
As with other GNU Coreutils utilities, the primary documentation is the info page.
From info coreutils dd invocation :
‘bs=BYTES’
Set both input and output block sizes to BYTES. This makes ‘dd’
read and write BYTES per block, overriding any ‘ibs’ and ‘obs’
settings. In addition, if no data-transforming ‘conv’ option is
specified, input is copied to the output as soon as it’s read, even
if it is smaller than the block size.
There are corresponding parameters for the individual read, write and conversion block sizes:
‘ibs=BYTES’
Set the input block size to BYTES. This makes ‘dd’ read BYTES per
block. The default is 512 bytes.
‘obs=BYTES’
Set the output block size to BYTES. This makes ‘dd’ write BYTES
per block. The default is 512 bytes.
‘cbs=BYTES’
Set the conversion block size to BYTES. When converting
variable-length records to fixed-length ones (‘conv=block’) or the
reverse (‘conv=unblock’), use BYTES as the fixed record length.
answered Apr 3 at 13:00
steeldriver
63k1198166
answered Apr 3 at 13:00
steeldriver
63k1198166
answered Apr 3 at 13:00
steeldriver
63k1198166
answered Apr 3 at 13:00
steeldriver
63k1198166
63k1198166
add a comment |Â
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512 Bytes per second would be painfully slow
– RoVo
Apr 3 at 13:01
I know, that was just the first number that popped into my head while writing that
– NerdOfLinux
Apr 3 at 13:02