sed & awk

sed awk describes two text processing programs that are mainstays of the UNIXprogrammers toolbox. sed is a stream editor for editing streams of text thatmight ... » 

sed awk describes two text processing programs that are mainstays of the UNIXprogrammers toolbox. sed is a stream editor for editing streams of text thatmight be too large to edit as a single file or that might be generated on thefly as part of a larger data processing step. The most common operation donewith sed is substitution replacing one block of text with another. awk is acomplete programming language. Unlike many conventional languages awk is datadriven you specify what kind of data you are interested in and theoperations to be performed when that data is found. awk does many things foryou including automatically opening and closing data files reading recordsbreaking the records up into fields and counting the records. While awkprovides the features of most conventional programming languages it alsoincludes some unconventional features such as extended regular expressionmatching and associative arrays. sed awk describes both programs in detailand includes a chapter of example sed and awk scripts. This edition coversfeatures of sed and awk that are mandated by the POSIX standard. This mostnotably affects awk where POSIX standardized a new variable CONVFMT and newfunctions toupper and tolower. The CONVFMT variable specifies theconversion format to use when converting numbers to strings awk used to useOFMT for this purpose. The toupper and tolower functions each take apresumably mixed case string argument and return a new version of the stringwith all letters translated to the corresponding case. In addition thisedition covers GNU sed newly available since the first edition. It alsoupdates the first edition coverage of Bell Labs nawk and GNU awk gawk coversmawk an additional freely available implementation of awk and brieflydiscusses three commercial versions of awk MKS awk Thompson Automation awktawk and Videosoft VSAwk. «