maybe_update

#!/bin/bash

# First parameter is file name.
# Second parameter is desired content.

decho () {
  if [[ "${debug:-0}" == "1" ]]; then
    echo "$@"
    return
  fi
}


updatefile () {
  local FILENAME
  local DIRNAME
  local FILEALREADYMATCHING
  local CURRENTFILECONTENT

  if [[ $# -ne 2 ]]; then
    decho returning                                    #echo if debug=1
    return 99
  fi

  FILENAME=$(basename "$1")
  DIRNAME=$(dirname "${FILENAME}")
  FILECONTENT="$2"

  mkdir -p "${DIRNAME}"
  if [[ -d "${DIRNAME}" ]] ; then
    FILEALREADYMATCHING=true
    if ! [[ -f "${FILENAME}" ]] ; then
      FILEALREADYMATCHING=false
      decho "file doesn't exist"                       #echo if debug=1
    else
      CURRENTFILECONTENT="$(IFS= cat "${FILENAME}")X"
      CURRENTFILECONTENT=${CURRENTFILECONTENT%?}
      decho "file exists"                              #echo if debug=1

      if [[ "${CURRENTFILECONTENT}" != "${FILECONTENT}" ]] ; then
        decho "content is different"                   #echo if debug=1
        FILEALREADYMATCHING=false
      fi
    fi
    if [[ "${FILEALREADYMATCHING}" != "true" ]] ; then
       decho "file doesnt match, making it match now"  #echo if debug=1
       decho "file is ${FILENAME} by the way"            #echo if debug=1
      printf '%s' "$2" > "${FILENAME}"
    fi
  fi
}


updatefile "$1" "$2"