DHEX(1) 						    BSD General Commands Manual 						   DHEX(1)

NAME

     dhex -- hex editor with a diff mode

SYNOPSIS

     dhex [-h] [-v] [-g] [-k] [-ab -ad -ah -ao base address] [-f config-file] [-m marker-file] [-ob -od -oh -oo offset] [-r searchlog]
	  [-sa -sab string (ascii)] [-sh -shb string (hex)] [-w searchlog] [file]
     dhex [-h] [-v] [-g] [-k] [-a1b -a1d -a1h -a1o base address 1] [-a2b -a2d -a2h -a2o base address 2] [-cb] [-cd upper-limit] [-cl]
	  [-f config-file] [-m marker-file] [-o1b -o1d -o1h -o1o offset1] [-o2b -o2d -o2h -o2o offset2] [-r1 searchlog1] [-r2 searchlog2]
	  [-s1a -s1ab -s1h -s1hb string (ascii/hex)] [-s2a -s2ab -s2h -s2hb string (ascii/hex)] [-w1 searchlog1] [-w2 searchlog2] [file1 file2]

DESCRIPTION

     dhex 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 dhex is called with two instead of one file as parameters.

OPTIONS

     All the options are case-insensitive and can be given as either upper- or lowercase characters.

     -ab -ad -ah -ao base address
		 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 [-ab] , as a decimal one with [-ad] , as a hexadecimal one with [-ah] or an
		 octal with [-ao].

     -a1b -a1d -a1h -a1o base address 1

     -a2b -a2d -a2h -a2o base address 2
		 For the diff mode, it is possible to set two different base addresses. Again, a binary address can be given as [-a1b -a2b] , as
		 decimal one with [-a1d -a2d] , as hexadecimal one with [-a1h -a2h] or an octal one with [-a1o -a2o].

		 This base address is calculated into the marker files as well as the searchlogs.

     -cb -cl	 Diff mode only: The input files can be correlated from the command line with the best -cb or longest -cl match. This is very
		 slow.

     -cd upper-limit
		 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.

     -f configfile
		 Usually, .dhexrc is being read from the invoker's home directory. With this parameter, any other config file can be loaded. See
		 dhexrc(5) for a description of its file format.

     -g 	 Shows the license

     -h 	 Shows the help screen

     -k 	 Starts the keyboard setup manually before any file is being loaded. This is very helpful when calling dhex from an exotic termi-
		 nal.

     -m markerfile
		 It is possible in dhex 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
		 dhex_markers(5).

     -ob -od -oh -oo offset
		 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 parame-
		 ters it is possible to start at any other location in the file. The cursorposition could be given as a binary number with [-ob] ,
		 as a decimal one with [-od] , as a hexadecimal one with [-oh] or an octal with [-oo].

     -o1b -o1d -o1h -o1o offset1

     -o2b -o2d -o2h -o2o offset2
		 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 [-o1b -o2b] , as decimal one with [-o1d -o2d] , as hexadecimal one with [-o1h -o2h] or an octal one with
		 [-o1o -o2o].

		 This way, the first few bytes in a file can be skipped, and just the rest can be compared.

     -r searchlog
		 When searching from the command line, the offsets are being read from this searchlog. Its format is being decribed in
		 dhex_searchlog(5).

     -r1 searchlog1

     -r2 searchlog2
		 When searching in two files simultanously, the offsets can be read from two different searchlogs.

     -sa -sab -sh -shb string
		 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 [-ob -od -oh -oo offset] present, the search will start there. It is possible to read and write search
		 logs with [-r searchlog] and [-w searchlog] respectively. With [-sa string] is being interpreted as ASCII.  [-sh string] inter-
		 prets it as hex. For backwards search, [-sab string] or [-shb string] can be applied.

     -s1a -s1ab -s1h -s1hb string1

     -s2a -s2ab -s2h -s2hb string2
		 In the diff mode, it is possible to search for two strings in two files simultanously.

     -v 	 Prints out the version of dhex.

     -w searchlog
		 When searching from the command line, write the results into this searchlog and quit. It is being written in the format described
		 in dhex_searchlog(5.)

     -w1 searchlog1

     -w2 searchlog2
		 When searching in two files simultanously, write the results from both searches into those log files.

USER INTERFACE

   General
     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.

   The keyboard setup
     When running dhex for the first time, without any configfile present, or with the parameter -k, the first screen shown is that of the key-
     board 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
     The main screen is broken down into three columns: The first column contains the offset within the file for the current line. The second col-
     umn 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 [-o] or [-a] 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.

   The goto screen
     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 [-m markerfile] parameter.
     dhex_markers(5) describes the format of the marker files.

   Searching
     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 log-
     files 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 dhex_searchlog(5).

     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.
     dhex_searchlog(5) describes the format of the searchlog.

   HexCal
     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.

   Correlation
     When dhex(1) 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 dif-
     ferences 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.

   Saving and quitting
     Pressing F10 (or its substitute) will close dhex.	In case there have been changes made to the file, a save dialog opens up. Here, it is pos-
     sible to select whether or not to write the changes back into the file.

FILES

     $HOME/.dhexrc: The default location of the config file. If the $HOME-variable is not set, its location has to be provided manually.

BUGS

     Report bugs to <dettus@dettus.net>.  Make sure to include DHEX somewhere in the subject.

AUTHOR

     Written by Thomas Dettbarn

SEE ALSO

     dhexrc(5), dhex_markers(5), dhex_searchlog(5)

BSD
								   May 12, 2012 							       BSD