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 is a hex editor. It can be used to alter individual bytes in  large  files.
 Since  it  is a text-mode programm based on ncurses, it can run in numerous
 scenarios.  Its special feature is the diff mode: With it, the user  has  a
 visual  tool  for file comparison. This mode is invoked when is called with
 two instead  of  one  file  as  parameters.   All  the  options  are  case-
 insensitive  and  can  be  given  as either upper- or lowercase characters.
 After loading a file, every address gets a base address other than 0.  With
 this, it is easier to work on partial memory dumps. The base address can be
 given as a binary one with , as a decimal one with , as a  hexadecimal  one
 with  or  an  octal  with  For  the  diff  mode,  it is possible to set two
 different base addresses. Again, a binary address can  be  given  as  ,  as
 decimal  one  with , as hexadecimal one with or an octal one with This base
 address is calculated into the marker files  as  well  as  the  searchlogs.
 Diff  mode  only:  The  input files can be correlated from the command line
 with the best or longest match. This is very slow.   Diff  mode  only:  The
 input  files  can  be  correlated  from  the  command line with the minimum
 difference. To improve  the  correlation  speed,  an  upper  limit  can  be
 provided. Usually, .dhexrc is being read from the invoker's home directory.
 With this parameter, any other  config  file  can  be  loaded.  See  for  a
 description  of its file format.  Shows the license Starts the hexcal Shows
 the help screen Starts the keyboard setup manually before any file is being
 loaded.  This  is very helpful when calling from an exotic terminal.  It is
 possible in to set bookmarks and store them in a markerfile for later  use.
 With  this parameter, the markerfile is being read at start time, making it
 unnecesarry to read them later  through  the  gui.  Their  file  format  is
 described  in  After  loading a file, the cursor is set to 0, and the first
 page of bytes is being shown on the screen. With one of those parameters it
 is  possible to start at any other location in the file. The cursorposition
 could be given as a binary number with , as a  decimal  one  with  ,  as  a
 hexadecimal  one with or an octal with For the diff mode, it is possible to
 set two different cursorpositions at start time. Again, the cursorpositions
 can be given as a binary number with , as decimal one with , as hexadecimal
 one with or an octal one with This way, the first few bytes in a  file  can
 be  skipped,  and  just  the rest can be compared.  When searching from the
 command line, the offsets are being read from this searchlog. Its format is
 being  decribed  in  When searching in two files simultanously, the offsets
 can be read from two different searchlogs.  Instead of setting  the  cursor
 offset to an absolute value, it is possible to search for a specific string
 from the command line. If there is an additional present, the  search  will
 start  there.  It  is  possible  to  read  and  write  search logs with and
 respectively. With is being interpreted as ASCII. interprets it as hex. For
 backwards  search,  or can be applied.  In the diff mode, it is possible to
 search for two strings in two files simultanously.  Prints out the  version
 of  When  searching  from  the  command  line,  write the results into this
 searchlog and quit. It is being written in the  format  described  in  When
 searching  in two files simultanously, write the results from both searches
 into those log files.  Menus have hotkeys, they are being  presented  in  a
 different color. To jump from one menu item to the next, the cursor keys or
 the TAB key can be used.  Input fields  can  be  closed  by  pressing  ESC,
 ENTER,  or any cursor key. Only pressing ESC will not save the changes made
 in there.  When running for the first time, without any configfile present,
 or  with  the  parameter -k, the first screen shown is that of the keyboard
 setup. In this screen, the program asks the user  to  press  certain  keys.
 Which  are  (in  order)  ESCAPE,  F1,  F2, F3, F4, F5, F6, F7, F8, F9, F10,
 BACKSPACE, DEL, ENTER, TAB, UP, DOWN, RIGHT, LEFT, PG UP,  PG  DOWN,  HOME,
 END. It also tells the user what it intends to do with those keys later. So
 the user can decide on any alternative he chooses. If he does not  want  to
 bind  a  specific function to a certain key, he can simply press ESCAPE and
 skip to the next question.  After pressing all the keys, the user can chose
 whether  or  not to write those keys into the config file.  The main screen
 is broken down into three columns: The first  column  contains  the  offset
 within  the file for the current line. The second column contains the bytes
 in the file in hex format. Finally,  the  third  coumn  contains  the  same
 bytes,  but  this  time  in ascii format. If a byte is not printable, it is
 being substituted with a '.'.  How many bytes are are being shown in a line
 depends  on  the  width of the terminal. For example, if the terminal is 80
 characters wide, 16 bytes are being shown in each line.   If  no  other  or
 parameter  was given at start time, the cursor is being set to offset 0. It
 is also being shown in the hex column. Here,  it  can  be  moved  with  the
 cursor  keys. When entering a hexadecimal number, the file is being edited.
 The file can be edited in the ascii column as well, simply by pressing  the
 TAB  key  (or  whichever key was substituted for it in the keyboard setup).
 Pressing TAB again will return the cursor to the hex  column.  Pressing  F9
 (or  its  substitute)  will undo the last of the changes. Changes are being
 shown in a differnt color. Editing is not possible in the diff mode.  Here,
 pressing  the  cursor keys will move both files synchronously.  Pressing F1
 (or its substitute) will open the Goto... screen. Here, it is  possible  to
 jump  to  a  specific address directly, without the need of scrolling there
 with the cursor keys. The address can be entered in the 'To' field,  either
 absolute  or  relative  (to  leap  over  a  specified  amount of bytes). An
 absolute address is being chosen by pressing '=', and  a  relative  one  by
 pressing  '+'  or  '-',  for  a  positive  or  negative  leap respectively.
 Regardless of the adressing mode, it has to be  entered  as  a  hexadecimal
 number.   It  is  also  possible to set up to ten bookmarks in this screen:
 Pressing '0'...'9' will select one of them. Moving the cursor to "Set"  and
 pressing  ENTER  will alter one of those book marks. The "Diff:" fields are
 showing the difference between the actual cursor position and the bookmark.
 Bookmarks  can  be stored and loaded, for this there are the "Save Markers"
 and "Load Markers" items on the bottom. Upon selecting  one  of  them,  the
 user is being prompted for a filename. It is possible to load a marker file
 at start time, by providing the parameter.  describes  the  format  of  the
 marker  files.   Pressing  F2  (or  its  subsitute) will open the Search...
 screen. Here, a short string can be entered (either in hex, or  in  ascii).
 If  no  logfiles  are  being  selected,  the  cursor  will jump to the next
 occurance of this search string upon selection of "Go". It can be chosen if
 the  search  is  supposed to be conducted forward of backwards.  To jump to
 the next occurance, F3 (or its substitute) has to be pressed.  To  jump  to
 the  previous  one,  F4  has  to be pressed. The search itself wraps at the
 edges of the file, meaning that when it reaches the end, it will start from
 the beginning and vice versa.  Searchlogs are an advanced way of searching:
 Writing to the searchlog does not jump the cursor from one occurance to the
 next.  Instead,  it will write the offsets of all of them into the logfile.
 Their format is described in Reading from this  searchlog  means  that  the
 search  does  not  cover the whole file: Only the addresses which have been
 provided in this file are being searched. Thus it is possible to search for
 specific  changes.  Like for example the number of lives stored in the save
 file of a game. describes the format of the searchlog.  Pressing F5 (or its
 substitute)  will  open  a  small  64  bit  calculator.  This calculator is
 capable of not only performing arithmetic operations (+, -, *, /,  modulo),
 but  also  logic  ones.  (and,  or, xor, shift). There are three columns to
 enter numbers as hexadecimals, decimals or in binary format.  Pressing  'x'
 will  close this screen. Using the command line argument will start it from
 the commandline.  When is  running  in  diff  mode,  pressing  F6  (or  its
 substitute)  will  open  the  dialog for file correlation. This will try to
 find the optimal offset between the two files. There are  three  algorithms
 available  for  finding  this offset: Searching for the best match (as many
 bytes as possible are the same), the longest  match  (as  many  consecutive
 bytes  match as possible), or the minimum difference (as little differences
 between the bytes as possible).  Even though it  seems  like  the  same  at
 first,  looking  for  the minimum difference is in fact faster. This can be
 improved even more, if the user  sets  an  upper  difference  limit.   Upon
 selecting  Go,  the  program  will search for the optimal offset. This will
 take some time.  Pressing F10 (or its substitute) will close In case  there
 have  been  changes  made  to the file, a save dialog opens up. Here, it is
 possible to select whether or not to write the changes back into the  file.
 $HOME/.dhexrc:  The  default  location  of  the  config file. If the $HOME-
 variable is not set, its location has to be provided manually.  Report bugs
 to Make sure to include DHEX somewhere in the subject.  Written by