git.subgeniuskitty.com - unix-history/.git/blob - usr/src/usr.bin/diff/diff3/diff3.1

.\"

.\" %sccs.include.redist.man%

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.\" @(#)diff3.1 6.3 (Berkeley) %G%

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.Dd

.Dt DIFF3 1

.Os BSD 4.4

.Sh NAME

.Nm diff3

.Nd 3-way differential file comparison

.Sh SYNOPSIS

.Nm diff3

.Op Fl exEX3

.Ar file1 file2 file3

.Sh DESCRIPTION

The

.Nm diff3

utility compares the contents of three different versions of a file,

.Ar file1 ,

.Ar file2

and

.Ar file3 ,

writing the result to the standard output.

The options describe different methods of merging and

purging

the separate versions into a new file.

.Nm Diff3

is used by

.Xr RCS 1

to merge specific versions or create

new versions.

.Pp

Options are:

.Tp Fl e

Produces output in a form suitable as an input script for the

.Xr ed 1

utility. The script may then be used to merge differences common

between all three files and differences specific to file1 and file3.

In other words, the

.Fl e

option ignores differences specific to file1 and file2, and those

specific to file2 and file3. It is useful for backing out changes

specific to file2 only.

.Tp Fl x

Produces an output script suitable for

.Xr ed 1

with changes

specific only to all three versions.

.Tp Fl 3

Produces an output script suitable for

.Xr ed 1

with changes

specific only to file3.

.Tp Fl E , X

Similar to

.Fl e

and

.Fl x ,

respectively, but treat overlapping changes (i.e., changes that would

be noted with ==== in the normal listing) differently. The overlapping

lines from both files will be inserted by the edit script, bracketed

by "<<<<<<" and ">>>>>>" lines.

.Tp

.Pp

The

.Fl E

option is used by RCS

.Xr merge 1

to insure that overlapping changes in the merged files are preserved

and brought to someone's attention.

.Pp

For example, suppose lines 7-8 are changed in both file1 and file2.

Applying the edit script generated by the command

.Pp

.Dl diff3 -E file1 file2 file3

.Pp

to file1 results in the file:

.Ds I

lines 1-6

of file1

<<<<<<< file1

lines 7-8

of file1

=======

lines 7-8

of file3

>>>>>>> file3

rest of file1

.De

.Pp

The default output of

.Nm diff3

makes notation of the differences between all files, and those differences

specific to each pair of files. The

changes are described by

the commands neccessary for

.Xr ed 1

to create the desired target from the different versions.

See

.Xr diff 1

for a description of the commands.

.Tw Fl

.Tp Li \&====

The lines beneath this notation are ranges of lines which are different

between all files.

.Tc Li \&====

.Va n

.Cx

The lines beneath this notation are ranges of lines which are exclusively

different in file

.Va n .

.Tp

.Sh EXAMPLES

.Pp

If three files were to contain:

.Ds I

.Cw mooxthree mooxthree mooxthree

.Cl file1 file2 file3

.Cl moo moo moo

.Cl moo too moon moon

.Cl moo three moo moo moo moo

.Cl tangent beam milk

.Cl moo moo sun butter

.Cl \tcloud beam

.Cl \tmoo moo

.Cw

.De

.Pp

The command line

.Pp

.Dl diff3 -e file1 file2 file3

.Pp

produces the following ed script:

.Pp

.Ds C

====1

1:2,4c

moo two

moo three

tangent

2:2c

3:2c

moon

====

1:5a

2:4,8c

beam

sun

cloud

moo moo

3:4,6c

milk

butter

beam

.De

.Sh FILES

.Dw /usr/bin/diff3

.Di L

.Dp Pa /tmp/d3?????

temporary files.

.Dp Pa /usr/bin/diff3

the executable.

.Dp

.Sh SEE ALSO

.Xr diff 1

.Xr ed 1

.Xr rcs 1

.Sh HISTORY

.Nm Diff3

appeared in Version 7 AT&T Unix.

.Sh BUGS

The

.Fl e

option

cannot catch and change

lines which have

.Sq Li \&.

as the first ans only character on the line.

The resulting script will fail on that line

as the

.Sq Li \&.

is an

.Xr ed 1

editing command.