{"product_id":"9781449396602","title":"sed \u0026 awk: UNIX Power Tools","description":"\u003cp\u003e\u003ci\u003esed \u0026amp; awk\u003c\/i\u003e describes two text processing programs that are mainstays of the UNIX programmer's toolbox.\u003ci\u003esed\u003c\/i\u003e is a \"stream editor\" for editing streams of text that might be too large to edit as a single file, or that might be generated on the fly as part of a larger data processing step. The most common operation done with \u003ci\u003esed\u003c\/i\u003e is substitution, replacing one block of text with another.\u003ci\u003eawk\u003c\/i\u003e is a complete programming language. Unlike many conventional  languages, \u003ci\u003eawk\u003c\/i\u003e is \"data driven\" -- you specify what kind of data you  are interested in and the operations to be performed when that data is  found. \u003ci\u003eawk\u003c\/i\u003e does many things for you, including automatically  opening and closing data files, reading records, breaking the records up  into fields, and counting the records. While \u003ci\u003eawk\u003c\/i\u003e provides the  features of most conventional programming languages, it also includes some  unconventional features, such as extended regular expression matching and  associative arrays. \u003ci\u003esed \u0026amp; awk\u003c\/i\u003e describes both programs in detail  and includes a chapter of example \u003ci\u003esed\u003c\/i\u003e and \u003ci\u003eawk\u003c\/i\u003e scripts.This edition covers features of \u003ci\u003esed\u003c\/i\u003e and \u003ci\u003eawk\u003c\/i\u003e that are  mandated by the POSIX standard. This most notably affects \u003ci\u003eawk\u003c\/i\u003e, where  POSIX standardized a new variable, CONVFMT, and new functions, \u003ci\u003etoupper\u003c\/i\u003e()  and \u003ci\u003etolower\u003c\/i\u003e(). The CONVFMT variable specifies the conversion format  to use when converting numbers to strings (\u003ci\u003eawk\u003c\/i\u003e used to use OFMT for this  purpose). The \u003ci\u003etoupper\u003c\/i\u003e() and \u003ci\u003etolower\u003c\/i\u003e() functions each take a  (presumably mixed case) string argument and return a new version of the  string with all letters translated to the corresponding case.In addition, this edition covers GNU \u003ci\u003esed\u003c\/i\u003e, newly available since the first edition. It also updates the first edition coverage of Bell Labs \u003ci\u003enawk\u003c\/i\u003e  and GNU \u003ci\u003eawk\u003c\/i\u003e (\u003ci\u003egawk\u003c\/i\u003e), covers \u003ci\u003emawk\u003c\/i\u003e, an additional freely  available implementation of \u003ci\u003eawk\u003c\/i\u003e, and briefly discusses three commercial versions of \u003ci\u003eawk\u003c\/i\u003e, MKS \u003ci\u003eawk\u003c\/i\u003e, Thompson Automation \u003ci\u003eawk\u003c\/i\u003e  (\u003ci\u003etawk\u003c\/i\u003e), and Videosoft (VSAwk).\u003c\/p\u003e","brand":"O'Reilly Media, Incorporated","offers":[{"title":"Default Title","offer_id":47154963153136,"sku":"9781449396602","price":17.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0737\/7593\/9824\/files\/9781449396602_p0.jpg?v=1763835205","url":"https:\/\/shop-qa.barnesandnoble.com\/products\/9781449396602","provider":"Barnes \u0026 Noble (DEV)","version":"1.0","type":"link"}