egrep-searches a file for a pattern using full regular expressions

egrep ”searches a file for a pattern using full regular expressions

 egrep [ bchilnsv ] [ e specialexpression ][ f filename ] [ strings ] [ filename ... ] 

egrep (expression grep) searches files for a pattern of characters and prints all lines that contain that pattern. egrep uses full regular expressions (expressions with string values that use the full set of alphanumeric and special characters) to match the patterns.

Example A.23.

 1   egrep 'TomJohn' datafile 2   egrep '^ [A-Z]+' file 

EXPLANATION

1. Displays all lines in datafile containing the pattern either Tom or John .

2. Displays all lines starting with one or more uppercase letters .