Actual examples of wdiff usage

This section presents a few examples of usage, most of them have been contributed by wdiff users.

• Change bars example. This example comes from a discussion with Joe Wells, `jbw@cs.bu.edu'. The following command produces a copy of new_file, shifted right one space to accommodate change bars since the last revision, ignoring those changes coming only from paragraph refilling. Any line with new or changed text will get a `|' in column 1. However, deleted text is not shown nor marked.

  wdiff -1n old_file new_file |
    sed -e 's/^/  /;/{+/s/^ /|/;s/{+//g;s/+}//g'
  

  Here is how it works. Word differences are found, paying attention only to additions, as requested by option `-1'. For bigger changes which span line boundaries, the insert bracket strings are repeated on each output line, as requested by option `-n'. This output is then reformatted with a sed script which shifts the text right two columns, turns the initial space into a bar only if there is some new text on that line, then removes all insert bracket strings.
• LaTeX example. This example has been provided by Steve Fisk, `fisk@polar.bowdoin.edu'. The following uses LaTeX to put deleted text in boxes, and new text in double boxes:

  wdiff -w "\fbox{" -x "}" -y "\fbox{\fbox{" -z "}}" ...
  

  works nicely.
• troff example. This example comes from Paul Fox, `pgf@cayman.com'. Using wdiff, with some troff-specific delimiters gives much better output. The delimiters I used:

  wdiff -w'\s-5' -x'\s0' -y'\fB' -z'\fP' ...
  

  This makes the pointsize of deletions 5 points smaller than normal, and emboldens insertions. Fantastic! I experimented with:

  wdiff -w'\fI' -x'\fP' -y'\fB' -z'\fP'
  

  since that's more like the defaults you use for terminals/printers, but since I actually use italics for emphasis in my documents, I thought the point size thing was clearer. I tried it on code, and it works surprisingly well there, too... Marty Leisner `leisner@eso.mc.xerox.com' says: In the previous example, you had smaller text being taken out and bold face inserted. I had smaller text being taken out and larger text being inserted, I'm using bold face for other things, so this is more clear.

  wdiff -w '\s-3' -x'\s0' -y'\s+3' -z'\s0'