csv2json

#!/bin/sh

main() {
    for f; do
        dir=$(dirname -- "$f")
        filename=$(basename -- "$f")
        case "$filename" in
            *.csv) outfilename=${filename%.*}.json ;;
            *)     outfilename=$filename ;;
        esac

        awk "$script" "$f" >|"$dir/$outfilename"
    done
}

script='
BEGIN {
  FS=","
}
{
  if (FNR == 1) {
    for (i = 0; i <= NF; i++) {
      fields[i] = $(i)
    }
  }
  else {
    printf "{ "

    sep=""
    for (i = 1; i <= NF; i++) {
      printf sep "\"" fields[i] "\":\"" $(i) "\""
      sep=", "
    }

    print " }"
  }
}'

main "$@"

csv2json.awk

#!/bin/awk -f

BEGIN {
  FS=","
}
{
  if (FNR == 1) {
    for (i = 0; i <= NF; i++) {
      fields[i] = $(i)
    }
  }
  else {
    printf "{ "

    sep=""
    for (i = 1; i <= NF; i++) {
      printf sep "\"" fields[i] "\":\"" $(i) "\""
      sep=", "
    }

    print " }"
  }
}