DD(1L) DD(1L) NNAAMMEE dd - convert a file while copying it SSYYNNOOPPSSIISS dddd [--help] [--version] [if=file] [of=file] [ibs=bytes] [obs=bytes] [bs=bytes] [cbs=bytes] [skip=blocks] [seek=blocks] [count=blocks] [conv={ascii,ebcdic,ibm,block,unblock,lcase,ucase,swab,noerror,notrunc, sync}] DDEESSCCRRIIPPTTIIOONN This manual page documents the GNU version of dddd. dddd copies a file (from the standard input to the standard output, by default) with a user-selectable blocksize, while optionally performing conversions on it. OOPPTTIIOONNSS Numbers can be followed by a multiplier: b=512, c=1, k=1024, w=2, xm=number m _-_-_h_e_l_p Print a usage message on standard output and exit successfully. _-_-_v_e_r_s_i_o_n Print version information on standard output then exit successfully. _i_f_=_f_i_l_e Read from _f_i_l_e instead of the standard input. _o_f_=_f_i_l_e Write to _f_i_l_e instead of the standard output. Unless _c_o_n_v_=_n_o_t_r_u_n_c is given, truncate _f_i_l_e to the size specified by _s_e_e_k_= (0 bytes if _s_e_e_k_= is not given). _i_b_s_=_b_y_t_e_s Read _b_y_t_e_s bytes at a time. _o_b_s_=_b_y_t_e_s Write _b_y_t_e_s bytes at a time. _b_s_=_b_y_t_e_s Read and write _b_y_t_e_s bytes at atime. Override ibs and obs. _c_b_s_=_b_y_t_e_s Convert _b_y_t_e_s bytes at a time. _s_k_i_p_=_b_l_o_c_k_s Skip _b_l_o_c_k_s ibs-sized blocks at start of input. _s_e_e_k_=_b_l_o_c_k_s Skip _b_l_o_c_k_s obs-sized blocks at start of output. FSF GNU File Utilities 1 DD(1L) DD(1L) _c_o_u_n_t_=_b_l_o_c_k_s Copy only _b_l_o_c_k_s ibs-sized input blocks. _c_o_n_v_=_c_o_n_v_e_r_s_i_o_n_[_,_c_o_n_v_e_r_s_i_o_n_._._._] Convert the file as specified by the _c_o_n_v_e_r_s_i_o_n arguments. Conversions: ascii Convert EBCDIC to ASCII. ebcdic Convert ASCII to EBCDIC. ibm Convert ASCII to alternate EBCDIC. block Pad newline-terminated records to size of cbs, replacing newline with trailing spaces. unblock Replace trailing spaces in cbs-sized block with newline. lcase Change uppercase characters to lowercase. ucase Change lowercase characters to uppercase. swab Swap every pair of input bytes. Unlike the Unix dd, this works when an odd number of bytes are read. If the input file contains an odd number of bytes, the last byte is simply copied (since there is nothing to swap it with). noerror Continue after read errors. notrunc Do not truncate the output file. sync Pad every input block to size of ibs with trailing NULs. FSF GNU File Utilities 2 .