

INVERT(1)	    UNIX Programmer's Manual		INVERT(1)


NNAAMMEE
     invert, lookup - create and access an inverted index

SSYYNNOOPPSSIISS
     iinnvveerrtt [option ... ] file ...

     llooookkuupp [option ... ]

DDEESSCCRRIIPPTTIIOONN
     _I_n_v_e_r_t creates an inverted index to one or more files.
     _L_o_o_k_u_p retrieves records from files for which an inverted
     index exists.  The inverted indices are intended for use
     with _b_i_b(1).

     _I_n_v_e_r_t creates one inverted index to all of its input files.
     The index must be stored in the current directory and may
     not be moved.  Input files may be absolute path names or
     paths relative to the current directory.  Each input file is
     viewed as a set of records; each record consists of non-
     blank lines; records are separated by blank lines.

     _L_o_o_k_u_p retrieves records based on its input (_s_t_d_i_n). Each
     line of input is a retrieval request.  All records that con-
     tain all of the keywords in the retrieval request are sent
     to _s_t_d_o_u_t. If there are no matching references, ``No refer-
     ences found.'' is sent to _s_t_d_o_u_t.	_L_o_o_k_u_p first searches in
     the user's private index (default INDEX) and then, if no
     references are found, in the system index
     (/usr/dict/papers/INDEX).	The system index was produced
     using _i_n_v_e_r_t with the default options; in general, the user
     is advised to use the defaults.

     Keywords are a sequence of non-white space characters with
     non-alphanumeric characters removed.  Keywords must be at
     least two characters and are truncated (default length is
     6).  Some common words are ignored.  Some lines of input are
     ignored for the purpose of collecting keywords.

     The following options are available for _i_n_v_e_r_t:

     -c _f_i_l_e

     -c_f_i_l_e  File contains common words, one per line.	Common
	     words are not used as keys.  (Default
	     /usr/new/lib/bmac/common.)

     -k _i

     -k_i     Maximum number of keys kept per record. (Default
	     100)

     -l _i


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INVERT(1)	    UNIX Programmer's Manual		INVERT(1)


     -l_i     Maximum length of keys. (Default 6)

     -p _f_i_l_e

     -p_f_i_l_e  File is the name of the private index file (output
	     of _i_n_v_e_r_t).  (Default is INDEX.) The index must be
	     stored in the current directory.  (Be careful of the
	     second form.  The shell will not know to expand the
	     file name.  E.g. -p~/index won't work; use
	     -p ~/index.)

     -s      Silent.  Suppress statistics.

     -%_s_t_r   Ignore lines that begin with %x where x is in _s_t_r.
	     (Default is CNOPVX. See _b_i_b(1) for explanation of
	     field names.)

     _L_o_o_k_u_p has only the options cc, ll, and pp with the same mean-
     ings as _b_i_b. In particular, the pp option can be followed by
     a list of comma separated index files.  These are searched
     in order from left to right until at least one reference is
     found.

FFIILLEESS
     INDEX		      inverted index
     /usr/tmp/invertxxxxxx    scratch file for invert
     /usr/new/lib/bmac/common	  default list of common words
     /usr/dict/papers/INDEX   default system index

SSEEEE AALLSSOO
     _A _U_N_I_X _B_i_b_l_i_o_g_r_a_p_h_i_c _D_a_t_a_b_a_s_e _F_a_c_i_l_i_t_y, Timothy A. Budd and
     Gary M. Levin, University of Arizona Technical Report 82-1,
     1982.
     bib(1)

DDIIAAGGNNOOSSTTIICCSS
     Messages indicating trouble accessing files are sent on
     _s_t_d_e_r_r. There is an explicit message on _s_t_d_o_u_t from _l_o_o_k_u_p
     if no references are found.

     _I_n_v_e_r_t produces a one line message of the form,
     %D documents   %D distinct keys  %D key occurrences.  This
     can be suppressed with the -s option.

     The message locate: first key (%s) matched too many refs
     indicates that the first key matched more references than
     could be stored in memory.  The simple solution is to use a
     less frequently occurring key as the first key in the cita-
     tion.

BBUUGGSS
     No attempt is made to check the compatibility between an


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INVERT(1)	    UNIX Programmer's Manual		INVERT(1)


     index and the files indexed.  The user must create a new
     index whenever the files that are indexed are modified.

     Attempting to invert a file containing unprintable charac-
     ters can cause chaos.


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