NAME

diffmk − mark differences between files

SYNOPSIS

diffmk name1 name2 name3

DESCRIPTION

Diffmk compares two versions of a file and creates a third file that includes “change mark” commands for nroff(1) or troff(1). Name1 and name2 are the old and new versions of the file.  Diffmk 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 ∗. 

If the characters | and ∗ are inappropriate, a copy of diffmk can be edited to change them (diffmk is a shell procedure). 

If anyone is so inclined, diffmk can be used to produce listings of C (or other) programs with changes marked. 

EXAMPLE

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

produces a listing of two versions of a C program with changes marked.  First the two versions are compared and a new file, "tmp", is created containing the change mark commands.  The temporary file is then passed to nroff(1) using the file "macs" which 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. 

SEE ALSO

diff(1), nroff(1), troff(1). 

BUGS

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

Version 2.1  —  January 02, 1985