custom-index - add a custom index to a local NCBI Entrez archive

custom-index  adds  a custom index for one or more specified fields to a local NCBI Entrez Archive on the
       basis of a supplied helper command that produces an Entrez-style XML index.  On Debian systems, some such
       helpers are /usr/share/doc/ncbi-entrez-direct/examples/idx-*.

EDIRECT_PUBMED_MASTER
              Local archive directory to use; expected to hold an absolute path.

       EDIRECT_PUBMED_WORKING
              Directory to hold intermediate subtrees; expected to hold an absolute path.  Defaults to the local
              archive directory when not set.

       custom-index - add a custom index to a local NCBI Entrez archive

helper Helper command into which to pipe each uncompressed document.

       field  Name of a field being indexed (e.g., ANUM).

index-extras(1), index-pubmed(1), rchive(1), xtract(1).

NCBI                                               2023-01-30                                    CUSTOM-INDEX(1)

custom-indexhelperfield ...