[Bash] extractBib: extract bib items from a source bibtex database for a given tex file

#!/bin/bash # extract bib items from a source bibtex database for a given tex file # usage: #          extractBib tex-file bibtex-database output-bibtex-file # e.g., #          extractBib mypaper.tex mybibtexdatabase.bib mypaper.bib # http://scriptdemo.blogspot.com function getkeys() {    texfile=$1    mykeys=`grep "cite.*{.*}" ${texfile} | sed -e 's/\ //g' | awk '{for (i=1; i<=NF;i++) {if ($i ~ /cite/) {print $i}}}' | sed -e 's/\}/\n/g' | awk -F\{ '{print $2}' | sed -e 's/\,/\n/g' | sed '/^[\ ]*[\ ]*$/d' | sort | uniq | sed '/^\\\\/d' | sed '/:/d'`     echo ${mykeys} } if [ $# -eq 3 ]; then    texfile=$1; bibfile=$2; outfile=$3 elif [ $# -eq 2 ]; then    texfile=$1; bibfile=$2; outfile="extractbib_"$1 else    echo "usage:"    echo "          extractBib tex-file bibtex-database output-bibtex-file"    exit fi # make sure no overwrite [ -e ${outfile} ] && echo "${outfile} exists alreay! exit" && exit allkeys=`getkeys ${texfile}` if [ ${#allkeys[*]} -ne 0 ]; then    touch ${outfile}    for eachkey in ${allkeys[*]}    do        #echo ${eachkey}        sed -ne "/${eachkey}/,/^[\ ]*\}$/p" ${bibfile} >> ${outfile}    done fi