.Dd February 2, 2015 .Dt DD 1 .Os ubase .Sh NAME .Nm dd .Nd convert and copy a file .Sh SYNOPSIS .Nm .Op Ar operand... .Sh DESCRIPTION .Nm copies the standard input to the standard output. By default input data is read and written in 64kB blocks. When finished, .Nm displays the number of records read and written as well as the total number of bytes copied. .Nm syncs the filesystem once it is done copying. If you want to disable that use the .Ar nosync option. .Sh OPTIONS .Bl -tag -width Ds .It Ar bs Ns Op Ar =N If .Ar bs is not specified, the default blocksize is 64kB. If .Ar bs is specified without setting it to a specific value then an optimal value between the source and target filesystem will be selected. If this process fails it will fallback to the system's pagesize. Adjust .Ar N to set the block size of the transfers in bytes. .It Ar count=N Copy only .Ar N input blocks. .It Ar direct Use direct I/O for data. .It Ar if=file Read input from .Ar file instead of the standard input. .It Ar nosync Do not sync the filesystem once we are done copying. .It Ar quiet Enable quiet output. .It Ar of=file Write output to .Ar file instead of the standard output. If an initial portion of the output .Ar file is skipped using the seek operand, the output file is truncated at that point. .It Ar seek=N Seek .Ar N blocks from the beginning of the output before copying. .It Ar skip=N Skip .Ar N blocks from the beginning of the input before copying. .It Ar conv=notrunc Do not truncate the output file. .El