filter script to convert Unix timestamp millisecond format into date format

timestamp2date_filter

#!/bin/bash

# 使い方
# cat xxx.json | jq -M . | timestamp2date_filter [| jq .]
# (jq のカラー出力には対応していないので -M でカラー無し出力後にフィルタする

IFS=$'\n'

TIMESTAMP_REGEXP=".*timestamp_?.*\":[[:blank:]]*([0-9]+)([0-9]{3})"

OS=$(uname)
if [ ${OS} != 'Darwin' ]; then
  OS="Linux"
fi

convert2date () {
  if [ ${OS} == "Darwin" ]; then
    TZ=Asia/Tokyo date -r $1 "+%Y-%m-%dT%H:%M:%S.$2 %z"
  else
    TZ=Asia/Tokyo date --date=@$1 "+%Y-%m-%dT%H:%M:%S.$2 %z"
  fi
}

while read -r line
do
  if [[ ${line} =~ ${TIMESTAMP_REGEXP} ]]; then
    timestamp=${BASH_REMATCH[1]}
    millisecond=${BASH_REMATCH[2]}
    date_value=$(convert2date ${timestamp} ${millisecond})
    replaced_line=$(echo ${line} | sed -Ee "s/${timestamp}${millisecond}/\"${date_value}\"/")
    echo ${replaced_line}
  else
    echo ${line}
  fi
done