


      DDDDIIIIFFFFFFFF((((1111))))                     ((((UUUUNNNNIIIIXXXX 5555....0000))))                    DDDDIIIIFFFFFFFF((((1111))))



      NNNNAAAAMMMMEEEE
           diff - differential file comparator

      SSSSYYYYNNNNTTTTAAAAXXXX
           ddddiiiiffffffff [ ----eeeeffffbbbbhhhh ] file1 file2

      DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
           _D_i_f_f tells what lines must be changed in two files to bring
           them into agreement.  If _f_i_l_e_1 (_f_i_l_e_2) is ----, the standard
           input is used.  If _f_i_l_e_1 (_f_i_l_e_2) is a directory, then a file
           in that directory with the name _f_i_l_e_2 (_f_i_l_e_1) is used.  The
           normal output contains lines of these forms:

                _n_1 aaaa _n_3,_n_4
                _n_1,_n_2 dddd _n_3
                _n_1,_n_2 cccc _n_3,_n_4

           These lines resemble _e_d commands to convert _f_i_l_e_1 into
           _f_i_l_e_2.  The numbers after the letters pertain to _f_i_l_e_2.  In
           fact, by exchanging aaaa for dddd and reading backward one may
           ascertain equally how to convert _f_i_l_e_2 into _f_i_l_e_1.  As in
           _e_d, identical pairs where _n_1 = _n_2 or _n_3 = _n_4 are abbreviated
           as a single number.

           Following each of these lines come all the lines that are
           affected in the first file flagged by <<<<, then all the lines
           that are affected in the second file flagged by >>>>.

           The ----bbbb option causes trailing blanks (spaces and tabs) to be
           ignored and other strings of blanks to compare equal.

           The ----eeee option produces a script of _a, _c and _d commands for
           the editor _e_d, which will recreate _f_i_l_e_2 from _f_i_l_e_1.  The ----ffff
           option produces a similar script, not useful with _e_d, in the
           opposite order.  In connection with ----eeee, the following shell
           program may help maintain multiple versions of a file.  Only
           an ancestral file ($1) and a chain of version-to-version _e_d
           scripts ($2,$3,...) made by _d_i_f_f need be on hand.  A
           ``latest version'' appears on the standard output.

                (shift; cat $*; echo '1,$p') | ed - $1

           Except in rare circumstances, _d_i_f_f finds a smallest
           sufficient set of file differences.

           Option ----hhhh does a fast, half-hearted job.  It works only when
           changed stretches are short and well separated, but does
           work on files of unlimited length.  Options ----eeee and ----ffff are
           unavailable with ----hhhh.

      FFFFIIIILLLLEEEESSSS
           /tmp/d?????



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      DDDDIIIIFFFFFFFF((((1111))))                     ((((UUUUNNNNIIIIXXXX 5555....0000))))                    DDDDIIIIFFFFFFFF((((1111))))



           /usr/lib/diffh for ----hhhh

      SSSSEEEEEEEE AAAALLLLSSSSOOOO
           cmp(1), comm(1), ed(1).

      DDDDIIIIAAAAGGGGNNNNOOOOSSSSTTTTIIIICCCCSSSS
           Exit status is 0 for no differences, 1 for some differences,
           2 for trouble.

      BBBBUUUUGGGGSSSS
           Editing scripts produced under the ----eeee or ----ffff option are naive
           about creating lines consisting of a single period (....).











































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