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fmerge(1)		    General Commands Manual		     fmerge(1)

NAME
       fmerge -	merge files

SYNOPSIS
       fmerge [	option...  ] basefile fileA fileB

       fmerge -Help

       fmerge -VERSion

DESCRIPTION
       The fmerge program is used to compare the changes between two different
       descendants of a	base file, and creates an output file  which  contains
       both sets of changes.  This is useful when two users both take the same
       version of a file and make independent edits to it, and then later want
       to create a file	which contains both sets of edits.  In such a use, the
       original	file that both sets of edits is	derived	 from  is  called  the
       base  file.   The  two files containing the edits are called file A and
       file B.

       The command:
	      fmerge basefile fileA fileB -o outputfile
       produces	the output file	which contains the edits contained in  file  A
       and  file  B,  based  on	the base file .	 If the	-Output	option was not
       used, or	if no outputfile is specified, then the	merged lines are typed
       to  the	standard output.  The order of specifying file A and file B is
       usually unimportant.

       The fmerge program can also be used to remove earlier edits made	 to  a
       module.	 To do this, make the version containing the edits you want to
       delete be the basefile.	Make the version previous to the edit you want
       deleted	be  file A.  Finally, make the most recent version of the file
       which contains the other	edits (including the one you want deleted)  be
       file  B.	  Then the result of merging will be the newest	version	of the
       module minus the	changes	made by	the edit you wanted removed.  For  ex-
       ample,  if  three  successive  versions	of  some module	have the names
       edit10, edit11 and edit12, and you want the changes done	by  edit11  to
       be  undone, but still want the changes done by edit12, then you use the
       command:
	      fmerge edit11 edit10 edit12 -o outputfile

       While merging the two sets of edits, fmerge may discover	conflicts.   A
       conflict	 occurs	when the same line of the base file is changed by both
       of the two sets of edits.  The change can be due	to new lines being in-
       serted, lines being deleted, or both.  When conflicts occur, the	output
       file contains conflict identification lines, which are lines containing
       the  string  '/-/-/-/'.	 These lines indicate the region where the two
       sets of edits are incompatible.	You must then edit the output file and
       remove  these  lines, and in addition correct the conflicts manually in
       order to	produce	the correct result.

OPTIONS
       The following options are understood:

       -Conflicts [ conflictfile ]
	       Since conflicts due to deletions	are invisible  in  the	output
	       file,  and  inserts  do	not specify which of the two edits in-
	       serted the lines, there is an alternative  output  format  from
	       the  fmerge program.  This output format	describes what happens
	       to each line of the base	file, so that conflicts	are easier  to
	       detect and fix.	The command:
		      fmerge basefile fileA fileB -c conflictfile
	       produces	 the  file  describing the results of the merge	in de-
	       tail.  If the -Conflicts	option is specified without  any  con-
	       flictfile  name,	 then  the  conflicts are send to the standard
	       output.

	       If there	are conflicts, and the -Conflicts options is not spec-
	       ified, the fmerge program will exit with	a status of 1.

	       The conflict file contains lines	which contain three characters
	       and then	some text.  The	first three characters	describe  what
	       is  happening to	the base file at that point.  These characters
	       are the following:

		      IA      This line	was inserted by	file A.

		      DA      This line	was deleted by file A.

		      IB      This line	was inserted by	file B.

		      DB      This line	was deleted by file B.

		      <blanks>
			      This line	is unchanged.

		      X	      This is a	conflict identification	line.

		      U	      There are	unspecified unchanged lines here.

	       Each set	of conflicts is	flagged	by three identification	lines.
	       The  first  line	 indicates  the	beginning of the conflict, and
	       specifies the line numbers for the base file and	two  divergent
	       files.  The second conflict identification line separates lines
	       changed by file A from lines changed by file B.	The third con-
	       flict identification indicates the end of the conflict.

	       You  can	edit this conflict file	to remove the conflicts.  This
	       involves	deleting the conflict identification lines, and	chang-
	       ing  the	 conflicting  lines  as	necessary to fix the conflict.
	       While doing this, remember to leave three blank	characters  at
	       the front of any	new lines you insert while correcting the con-
	       flicts.	When you are done, there should	be no lines which  be-
	       gin with	an 'X' in the file.  All other lines can remain.  Then
	       you can use the command:
		      fmerge conflictfile -o outputfile
	       to create the new output	file which has the desired data.  Once
	       again,  if  no -Output option or	outputfile is used, the	output
	       is send to the standard output.

       -Unchanged number
	       Besides physical	conflicts, there  can  be  logical  conflicts.
	       These are changes made to different lines in the	base file such
	       that the	program	is no longer correct.  Such  conflicts	cannot
	       be  detected  by	 a program, and	so these must be checked manu-
	       ally.  In order to make this process easier, the	-Unchanged op-
	       tion  can  be  used  to reduce the size of the conflict file to
	       only include regions near changed lines.	 This file can then be
	       examined	 in order to detect possible logical conflicts.	 As an
	       example,	the command:
		      fmerge basefile fileA fileB -c -u	3
	       will send to the	standard output	all  changes  made  by	either
	       sets of edits, with only	three unchanged	lines surrounding each
	       edit.

	       When using the -Unchanged option, the conflict file  will  con-
	       tain lines starting with	'U'.  These represent unchanged	lines,
	       and the number following	the letter is the number of  unchanged
	       lines.	The  resulting conflict	file cannot be read to produce
	       an output file because of the missing lines.  If	 this  is  at-
	       tempted,	an error will be generated.

	       It  is  possible	to use both -Output and	-Conflicts in the same
	       command.	 Thus you can produce the output file which  you  hope
	       is  correct,  and  also produce the conflict file which you can
	       use to check for	logical	conflicts.

       -Verbose	[ number ]
	       This option can be specified with any other action, and outputs
	       status  information  about the progress of the action.  This is
	       useful for debugging of problems, or just  for  amusement  when
	       the  system is slow or a	large file is being processed.	It ac-
	       cepts a numeric argument	to indicate the	verbosity for  output.
	       The levels are as follows:

	       0   No output at	all (except for	errors).

	       1   Single-line output describing action	(default).

	       2   Detailed status as action proceeds.

       -Failures number
	       This option restricts the number	of physical conflicts that are
	       allowed before failing.	This is	used if	you are	not interested
	       in the results if there are too many conflicts.

       -Ignore
	       Ignore all conflicts.

       -Ignore_Identical_Conflicts
	       The option may be used to suppress conflicts which make identi-
	       cal deletes, or identical inserts, or identical changes.	  This
	       is often	desirable when merging two source code branches.

Reference Manual		     FHist			     fmerge(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS

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