The main advantage of using extended grep is that additional regular expression metacharacters (see Table 3.4) have been added to the basic set. With the -E extension, Gnu grep allows the use of these new metacharacters.
|Metacharacter||Function||Example||What It Matches|
|^||Beginning of line anchor||^love||Matches all lines beginning with love.|
|$||End of line anchor||love$||Matches all lines ending with love.|
|.||Matches one character||l..e||Matches lines containing an l, followed by two characters, followed by an e.|
|*||Matches zero or more characters||*love||Matches lines with zero or more spaces, of the preceding characters followed by the pattern love.|
|[ ]||Matches one ...|