Shell Script function to change postgresql values

postgresql_config.sh

# Error Codes
# 1: No variable name specified
# 2: No value found for variable
# If wanna save name = 'value' (between quotes), use: postgresql_config 12 foo \'bar\' (escaped)
postgresql_config() {
  VERSION=$1
  NAME=$2
  VALUE=$3
  MATCHED=0

  set -x

  [ -z $VERSION -o -z $NAME ] && echo "Use postgresql_config <cluster_version> <setting> <value>\nIf no value is passed, the current value will be returned"# && exit 1
  CONFIG_FILE="/etc/postgresql/${VERSION}/main/postgresql.conf"

  if [ -z $VALUE ]; then
    value=`egrep -o "^${NAME} = [^[:space:]]+" ${CONFIG_FILE} |cut -d "=" -f2| sed -e 's/[[:space:]]*//'`

    # if not found, return 2
    [ -z $value ] && exit 2

    # return the value found
    echo $value
  else
    # check if variable exists
    egrep -i "^#?${NAME} = " ${CONFIG_FILE} > /dev/null

    # if exists
    if [ $? -eq 0 ]; then
      ESCAPED_VALUE=${VALUE//\//\\/}
      # replace

      # Matches name = ''
      egrep -i "^#?${NAME} = ''" ${CONFIG_FILE} > /dev/null
      if [ $? -eq 0 ]; then
        MATCHED=1
        POSTGRESQL_NEEDS_RELOAD=1
        sed -i "s/^\(#\)\{0,1\}${NAME} = ''/${NAME} = '${ESCAPED_VALUE}'/g" ${CONFIG_FILE}
      fi

      # Matches name = 'value'
      egrep -i "^#?${NAME} = '[^[:space:]]+'" ${CONFIG_FILE} > /dev/null
      if [ $? -eq 0 -a $MATCHED -eq 0 ]; then
        MATCHED=1

        egrep -i "^${NAME} = '${VALUE}'" ${CONFIG_FILE} > /dev/null
        if [ $? -ne 0 ]; then
          sed -i "s/^\(#\)\{0,1\}${NAME} = '\([^[:space:]]\{0,\}\)'/${NAME} = '${ESCAPED_VALUE}'/g" ${CONFIG_FILE}
          POSTGRESQL_NEEDS_RELOAD=1
        fi
      fi

      # Matches name = value
      egrep -i "^#?${NAME} = [^[:space:]^']+" ${CONFIG_FILE} > /dev/null
      if [ $? -eq 0 -a $MATCHED -eq 0 ]; then
        MATCHED=1

        egrep -i "^${NAME} = ${VALUE}" ${CONFIG_FILE} > /dev/null
        if [ $? -ne 0 ]; then
          sed -i "s/^\(#\)\{0,1\}${NAME} = \([^[:space:]]\{0,\}\)/${NAME} = ${ESCAPED_VALUE}/g" ${CONFIG_FILE}
          POSTGRESQL_NEEDS_RELOAD=1
        fi
      fi
    else
      # else append
      echo "${NAME} = ${VALUE}" >> ${CONFIG_FILE}
    fi
  fi
}