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$ man xxd
XXD(1)           General Commands Manual          XXD(1)

NAME
       xxd - make a hexdump or do the reverse.

SYNOPSIS
       xxd -h[elp]
       xxd [options] [infile [outfile]]
       xxd -r[evert] [options] [infile [outfile]]

DESCRIPTION
       xxd  creates  a hex dump of a given file or stan‐
       dard input.  It can also convert a hex dump  back
       to  its  original  binary form.  Like uuencode(1)
       and uudecode(1) it  allows  the  transmission  of
       binary  data  in  a `mail-safe' ASCII representa‐
       tion, but has the advantage of decoding to  stan‐
       dard output.  Moreover, it can be used to perform
       binary file patching.

OPTIONS
       If no infile is given, standard  input  is  read.
       If  infile  is specified as a `-' character, then