Name

lxprintf — Format text extracted from an XML document

Synopsis

lxprintf [ -xmlns[:prefix]=uri ...] [ -e each-query ] format item-query ... [ input-file ]

Description

lxprintf extracts text from an XML document and formats it according the format argument, which resembles that of printf() in C. For each item in the format there must be an item-query argument. If an each-query is specified with -e, the item-queries are applied relative to each element matching the each-query, otherwise they are applied once at the document root.

The input-file argument may be a URI instead of a filename. If no input-file argument is given, standard input is used.

-xmlns[:prefix]=uri

binds a prefix (or the default namespace) to a URI for use in XPath queries.

-e each-query

an XPath query selecting elements to be processed. For each matching element, the format is called with the results of evaluating the item-queries relative to that element.

format

a C-style format string. The format specifiers allowed are %s (string), %f (floating-point), %d (integer), and %% (percent sign). Field width and precision may be specified (see the examples below). The escapes \n (newline), \r (carriage return), \t (tab), and \a (alert, i.e. bell) are also allowed.

item-query

an XPath query which is evaluated to produce a value to be formatted. The result is converted to a string or number as appropriate for the corresponding format specifier.

Examples

In these examples, we assume a file of products and their prices containing the following data: 

<products>
  <product price="3">Chicken</product>
  <product price="11.50">Lobster</product>
  <product price=".20">Apple</product>
  <product price="1.09">Milk (2 litres)</product>
</products>

lxprintf "$%.2f\n" "//product[. = 'Chicken']/@price" <prices.xml

Print the price of a chicken as a number with two decimal places. The output is: 

$3.00

lxprintf -e product "%-20s $%5.2f\n" . @price <prices.xml

Print a list of products and their prices. The product name will be padded to appear at the left of a 20-character field, and the price will be padded to appear at the right of a 5-character field. The output is: 

Chicken              $ 3.00
Lobster              $11.50
Apple                $ 0.20
Milk (2 litres)      $ 1.09