AT&T UNIX™PC Unix System V Users Manual - tenox

DIFF ( 1) DIFF ( 1)
-e producing a script of a, c and d commands for the editor
ed, which will recreate file2 from filel . In connection
with -e, the following shell program may help
maintain multiple versions of a file. Only an ancestral
file ($1) and a chain of version-to-version ed scripts
($2,$3, ... ) made by diff need be on hand. A 'latest version'
appears on the standard output.
(shift; cat $*; echo '1,$p ') I ed - $1
Extra commands are added to the output when comparing
directories with -e, so that the result is a sh ( 1)
script for converting text files which are common to the
two directories from their state in dir 1 to their state in
dir2.
-f produces a script similar to that of -e, not useful with
ed, and in the opposite order.
-c produces a diff with lines of context. The default is to
present 3 lines of context and may be changed, e.g to
10, by -clO. With -c the output format is modified
slightly: the output beginning with identification of the
files involved and their creation dates and then each
change is separated by a line with a dozen *'s. The
lines removed from filel are marked with '- '; those
added to file2 are marked '+'. Lines which are changed
from one file to the other are marked in both files with
'f'.
-h does a fast, half-hearted job. It works only when
changed stretches are short and well separated, but does
work on files of unlimited length.
-Dstring
causes diff to create a merged version of filel and file2
on the standard output, with C preprocessor controls
included so that a compilation of the result without
defining string is equivalent to compiling filel, while
defining string will yield file2.
-b causes trailing blanks (spaces and tabs) to be ignored,
and other strings of blanks to compare equal.
FILES
/tmp / d?????
/usr/lib/diffh for -h
/bin/pr
SEE ALSO
cmp( 1), cc( 1), comm(1), ed( 1), diff3( 1)
DIAGNOSTICS
Exit status is 0 for no differences, 1 for some, 2 for trouble.
BUGS
Editing scripts produced under the -e or -f option are naive
about creating lines consisting of a single '.'
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