dd.1 (1983B)
1 .Dd April 28, 2020 2 .Dt DD 1 3 .Os sbase 4 .Sh NAME 5 .Nm dd 6 .Nd convert and copy a file 7 .Sh SYNOPSIS 8 .Nm 9 .Op Ar operand Ns ... 10 .Sh DESCRIPTION 11 .Nm 12 copies its input to its output, possibly after conversion, using 13 the specified block sizes, 14 .Pp 15 The following operands are available: 16 .Bl -tag -width ibs=expr 17 .It Cm if= Ns Ar file 18 Read from the file named by 19 .Ar file 20 instead of standard input. 21 .It Cm of= Ns Ar file 22 Write to the file named by 23 .Ar file 24 instead of standard output. 25 .It Cm ibs= Ns Ar expr 26 Set the input block size to 27 .Ar expr 28 (defaults to 512). 29 .It Cm obs= Ns Ar expr 30 Set the output block size to 31 .Ar expr 32 (defaults to 512). 33 .It Cm bs= Ns Ar expr 34 Set the input and output block sizes to 35 .Ar expr . 36 Additionally, if no conversion other than 37 .Cm noerror , 38 .Cm notrunc , 39 or 40 .Cm sync 41 is specified, input blocks are copied as single output blocks, even 42 when the input block is short. 43 .It Cm skip= Ns Ar n 44 Skip 45 .Ar n 46 input blocks before starting to copy. 47 .It Cm seek= Ns Ar n 48 Skip 49 .Ar n 50 output blocks before starting to copy. 51 .It Cm count= Ns Ar n 52 Copy at most 53 .Ar n 54 input blocks. 55 .It Cm conv= Ns Ar value Ns Op , Ns Ar value Ns ... 56 Apply the conversions specified by 57 .Ar value . 58 .Bl -tag -width Ds 59 .It Cm lcase 60 Map uppercase characters to the corresponding lowercase character 61 using 62 .Fn tolower . 63 .It Cm ucase 64 Map lowercase characters to the corresponding uppercase character 65 using 66 .Fn toupper . 67 .It Cm swab 68 Swap each pair of bytes in the input block. 69 If there is an odd number of bytes in a block, the last one is 70 unmodified. 71 .It Cm noerror 72 In case of an error reading from the input, do not fail. 73 Instead, print a diagnostic message and a summary of the current 74 status. 75 .It Cm notrunc 76 Do not truncate the output file. 77 .It Cm sync 78 In case of a partial input block, pad with null bytes to form a 79 complete block. 80 .El 81 .El 82 .Sh STANDARDS 83 The 84 .Nm 85 utility is compliant with the 86 .St -p1003.1-2008 87 specification, except that it does not implement the 88 .Cm block 89 and 90 .Cm unblock 91 conversions.