diffmk.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

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.TH diffmk 1
.SH Name
diffmk \- mark differences between files
.SH Syntax
.B diffmk
\fIname1 name2 name3\fR
.SH Description
.NXR "diffmk command"
.NXR "file" "comparing"
The
.PN diffmk
command
compares two versions of a file and creates a
third file that includes ``change mark'' commands for
.PN nroff
or
.PN troff .
The
.I name1\^
and
.I name2\^
are the old and new versions of the file.
The
.PN diffmk
command generates
.IR name3 ,
which contains the lines of
.I name2\^
plus inserted formatter ``change mark''
.RB ( \&.mc )
requests.
When
.I name3\^
is formatted,
changed or inserted text is shown by \(bv at the right
margin of each line.
The position of deleted text is shown by a single
.BR \(** .
.PP
The
.PN diffmk\^
command
can be used to produce listings of C (or other)
programs with changes marked.
A typical command line for such use is the following:
.EX
diffmk \|old.c \|new.c \|tmp; \|nroff \|macs \|tmp \|\(bv \|pr
.EE
In this example the file
.B macs
contains:
.RS
.PP
.nf
\&.pl \|1
\&.ll \|77
\&.nf
\&.eo
\&.nc \|\*`
.fi
.RE
.PP
The
.B \&.ll
request might specify a different line length, depending on the
nature of the program being printed.
The
.B \&.eo
and
.B \&.nc
requests are probably needed only for C programs.
.PP
If the characters \(bv and
.B \(**
are inappropriate,
a copy of
.PN diffmk
can be edited to change them.
The
.PN diffmk
command
is a shell procedure.
.SH Restrictions
.NXR "diffmk command" "restricted"
Aesthetic considerations may dictate manual adjustment of some output.
File differences involving only formatting requests may produce undesirable
output,
that is, replacing
.B \&.sp
by
.B \&.sp 2
will
produce a ``change mark'' on the preceding or following line of output.
.SH See Also
cmp(1), comm(1), diff(1), nroff(1), join(1), sccsdiff(1), 
troff(1), uniq(1)