Article 2347 of comp.text.tex:
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From: fritzke@immd2.informatik.uni-erlangen.de (B. Fritzke)
Newsgroups: comp.text.tex
Subject: BIBTEX to REFER conversion program (here it is)
Message-ID: <3065@medusa.informatik.uni-erlangen.de>
Date: 13 Aug 90 11:13:07 GMT
Organization: Universitaet Erlangen, CS-Dep. IMMD II
Lines: 139

Recently I posted a request for a program to convert bibliographic 
references in the bibtex format to the refer format.

Beneath a lot of 'me too!'-messages I got an answer with an 
awk script, that could do part of the job. After some iterations
of improvement there now exist a pretty good version, that fits
at least my needs.

Because many people seem to be interested in the program, I post it
to this newsgroup.

How to make it run:
  1. put the stuff after the cut-line in a file called tex2refer (or t2r or so)
  2. Make that file executable by typing
       chmod u+x tex2refer
     on your Unix system

Bernd Fritzke

Bernd Fritzke ------>  e-mail: fritzke@immd2.informatik.uni-erlangen.de
University of Erlangen, CS IMMD II, Martensstr. 3,  8520 Erlangen (FRG)

--------------------------------- cut here -----------------------------------
#! /bin/sh
#
# tex2refer - converts bibtex entries to refer entries
#
# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
# This software comes on a 'as is'-basis.
# No guarantee for the correctness is given and no 'service' is provided 
# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
#
# This program (an awk skript) converts bibliographic references from the
# bibtex-format to the refer-format.
# it reads from stdin and writes to stdout:
#
# usage: tex2refer < file.bib > file.refer
#
# Be aware, that some information is neccessarily lost, because 
#
#   * several bibtex field names are mapped to the same refer filed name
#      e.g. publisher, organization and school are all mapped to %I
#   * refer doesn't support types for references (like @inproceedings, @article)
#     (therefore the inverse mapping refer2tex is mostly based on heuristics)
#
# In this program are only the more important (I.M.H.O.) field names covered.
# If tex2refer encounters unknown field names, it will ignore them but store their
# names in a list, which is displayed after the conversion process.
#
# With this list the program can easily be extended by adding entries to the 
# associative array 'refer'
#
#
# Thanks to Lee, who provided the main part of the program and added
# some useful comments for readability
#
# Bernd Fritzke (fritzke@immd2.informatik.uni-erlangen.de)
# August 1990
#

gawk ' #gnu awk, but works probably also with other versions
BEGIN {
    FS = " "
    refer["author"] = "%A"
    refer["AUTHOR"] = "%A"
    refer["address"] = "%C"
    refer["ADDRESS"] = "%C"
    refer["year"] = "%D"
    refer["YEAR"] = "%D"
    refer["publisher"] = "%I"
    refer["PUBLISHER"] = "%I"
    refer["journal"] = "%J"
    refer["JOURNAL"] = "%J"
    refer["keywords"] = "%K"
    refer["KEYWORDS"] = "%K"
    refer["pages"] = "%P"
    refer["PAGES"] = "%P"
    refer["title"] = "%T"
    refer["TITLE"] = "%T"
    refer["volume"] = "%V"
    refer["VOLUME"] = "%V"
    refer["city"] = "%C"
    refer["CITY"] = "%C"
    refer["booktitle"] = "%B"
    refer["BOOKTITLE"] = "%B"
    refer["note"] = "%o"
    refer["NOTE"] = "%o"
    refer["organization"] = "%I"
    refer["ORGANIZATION"] = "%I"
    refer["school"] = "%I"
    refer["SCHOOL"] = "%I"
}

/^@/	{next}   # reference type (not supported by refer) next line
# ---> "next" makes awk goto the start of the awk script & read the next
#	line of input, so here it is making it ignore lines starting
#	with an @ sign.

# ensure that an = signs is surrounded by space:
/\=/ { # "=" must be preceeded by `\` , also in line below 
    gsub(/\=/, " & ") # this may cause NF to be updated...
    # Warning -- do not put single quotes in comments!  This does not
    # work reliably in a shell script.
}

($1 in refer && $2 == "=") { # Begin of a bibtex field definition
    gsub(/[{}]/, "")  # deleting curly brackets
    gsub(/,$/, "")    # deleting commas at end of line
    printf "%s ", refer[$1]
    for (i = 3; i <= NF; i++) { # Loop over the keywords ($2 is "=")
	printf " %s", $i        # and print them
    }
    printf "\n" # newline on the end of the refer entry
}

(!($1 in refer) && $2 == "=") { #collect unknown keywords
    unknown[$1] = 1
    next
}

/[^	 ]/ {
    if ($2 != "=") { # This is not a first line of an entry
	# In this case, we are dealing with a continuation line.
	gsub(/[{}]/, "")  # deleting curly braces
	gsub(/,$/, "")    # deleting commas at end of line
	printf "   " 
	for (i = 1; i <= NF; i++) { # Loop over all the keywords 
	    printf " %s", $i        # and print them
	}
	printf "\n" # newline on the end of the refer entry
    }
}

END {
	for (a in unknown) {
	    print "------- unknown keyword:    " a 
	}
}
' ${@+"$@"}