Regular Expressions and Filters
Sunil Kumar Singh · 2021
A regular expression, referred to as regex or regexp , is represented by a set of characters that is used to search and match patterns in a string or to simplify the solution of text manipulation problems. This chapter briefs regular expressions, an elaborate pattern-matching concept, along with POSIX Basic Regular Expression (BRE) and POSIX Extended Regular Expression (ERE) metacharacters. Further, you also get to know about the grep family which handles the pattern search, edit, and replace operations. At this point, some basic regular filter commands are also described, such as comm, cut, expand, head, tail, more, less, split, tee, and zcat. Chapters 6 and 7 discuss two powerful advanced filters—sed and awk.