{"product_id":"sed-awk","title":"sed \u0026 awk","description":"sed \u0026amp; awk describes two text processing programs that are mainstays of the UNIX programmer's toolbox. sed 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 sed is substitution, replacing one block of text with another. awk is a complete programming language. Unlike many conventional  languages, awk is \"data driven\" -- you specify what kind of data you  are interested in and the operations to be performed when that data is  found. awk 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 awk provides the  features of most conventional programming languages, it also includes some  unconventional features, such as extended regular expression matching and  associative arrays. sed \u0026amp; awk describes both programs in detail  and includes a chapter of example sed and awk scripts. This edition covers features of sed and awk that are  mandated by the POSIX standard.\nThis most notably affects awk, where  POSIX standardized a new variable, CONVFMT, and new functions, toupper()  and tolower(). The CONVFMT variable specifies the conversion format  to use when converting numbers to strings (awk used to use OFMT for this  purpose). The toupper() and tolower() 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 sed, newly available since the first edition. It also updates the first edition coverage of Bell Labs nawk  and GNU awk (gawk), covers mawk, an additional freely  available implementation of awk, and briefly discusses three commercial versions of awk, MKS awk, Thompson Automation awk  (tawk), and Videosoft (VSAwk).","brand":"O'Reilly Media","offers":[{"title":"Default Title","offer_id":54258135957848,"sku":"9781565922259","price":49.99,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0278\/1295\/4195\/files\/9781565922259_1ebac643-02de-4bca-b86b-f59014b4af0e.jpg?v=1778584516","url":"https:\/\/agendabookshop.com\/products\/sed-awk","provider":"Agenda Bookshop","version":"1.0","type":"link"}