geoff@utcsstat.UUCP (Geoffrey Collyer) (11/08/83)
The following bugs are present in look on at least V7 and 4.1BSD.
The -d (dictionary order) option does not work as advertised. It
ignores whitespace during comparison, despite look(1), which says
d `Dictionary' order: only letters, digits, tabs and
blanks participate in comparisons.
The fix is to change, in canon(),
if (!isalnum(c))
to
if ((!isascii(c) || !isalnum(c)) &&
c != ' ' && c != '\t')
There is an undocumented -t option, identical to that of sort(1).
There are lots of coding botches. Look uses continue statements
liberally, and returns from main() without a value. In canon(),
isalnum and isupper are used without testing isascii first. The fix
for isalnum is given above, the other correction is to change
if (isupper(c))
*new += 'a' - 'A';
to
if (isascii(c) && isupper(c))
*new = tolower(c);
The new version also uses tolower portably rather than the previous,
less-portable addition of a magic quantity.
Once the above fixes are applied, look may be used to look up the
spelling of a word (in /usr/dict/words) much more rapidly than egrep
can or to search a phonebook. Look performs a binary search on sorted
text files and so could be used to look for poor passwords in
passwd(1) [strong hint].
Geoff Collyer, U. of Toronto