4.3BSD/usr/contrib/rcs/doc/rdiff.ms

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.TL
Changes to diff
.PP
The options -e and -f generate edit scripts that can be used to
regenerate one file from the other. In these scripts, groups of text lines
following the a (add) and c (change) commands are terminated with a
line consisting of a single '.'. This is a botch. I added a new option, -n,
which works like -f, except that groups of text lines are not terminated
with '.'. Instead, the number of text lines is given in the command itself.
The commands are generated in order of increasing line numbers.
Option -h does not support -n.

.nf
Commands generated by diff -n

d l n      delete lines l..l+n-1
a l n      add the following n lines after line l.
....
....