Dell W-7030 AOS 6.4.x User Guide - Page 1108

Regular Expression Repetition Operators Repetition operators are quantifiers that describe how many times to search for a specified string. Use them in conjunction with the character-matching operators in Table 243 to search for multiple characters. Table 243: Regular expression repetition operators Operator Description Sample ? Match any character one egrep "?erd" sample text time if it exists Result Matches berd, herd, etc., erd * Match declared element egrep "n.*rd" sample.txt Matches nerd, nrd, neard, etc. multiple times if it exists + Match declared element egrep "[n]+erd" sample.txt Matches nerd, nnerd, etc., but one or more times not erd {n} Match declared element egrep "[a-z]{2}erd" exactly n times sample.txt Matches cherd, blerd, etc., but not nerd, erd, buzzerd, etc. {n,} Match declared element at egrep ".{2,}erd" sample.txt Matches cherd and buzzerd, least n times but not nerd {n,N} Match declared element at least n times, but not more than N times egrep "n[e]{1,2}rd" sample.txt Matches nerd and neerd Regular Expression Anchors Anchors describe where to match the pattern, and are a handy tool for searching for common string combinations. Some of the anchor examples use the vi line editor command :s, which stands for substitute. That command uses the syntax: s/pattern_to_match/pattern_to_substitute. Table 244: Regular expression anchors Operator Description ^ Match at the beginning of a line $ Match at the end of a line \< Match at the beginning of a word Sample s/^/blah / Result Inserts "blah" at the beginning of the line s/$/ blah/ Inserts " blah" at the end of the line s/\