Name

diffmk − mark differences between files

Syntax

diffmk name1 name2 name3

Description

The diffmk command compares two versions of a file and creates a third file that includes “change mark” commands for nroff or troff. The name1 and name2 are the old and new versions of the file.  The diffmk command generates name3, which contains the lines of name2 plus inserted formatter “change mark” (.mc) requests.  When name3 is formatted, changed or inserted text is shown by │ at the right margin of each line.  The position of deleted text is shown by a single ∗. 

The 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:

diffmk old.c new.c tmp; nroff macs tmp │ pr

In this example the file macs contains:

.pl 1
.ll 77
.nf
.eo
.nc `

The .ll request might specify a different line length, depending on the nature of the program being printed.  The .eo and .nc requests are probably needed only for C programs. 

If the characters │ and ∗ are inappropriate, a copy of diffmk can be edited to change them. The diffmk command is a shell procedure.

Restrictions

Aesthetic considerations may dictate manual adjustment of some output.  File differences involving only formatting requests may produce undesirable output, that is, replacing .sp by .sp 2 will produce a “change mark” on the preceding or following line of output. 

See Also

cmp(1), comm(1), diff(1), nroff(1), join(1), sccsdiff(1), troff(1), uniq(1)