Linux egrep Commands

The Linux egrep command is used to find the specified string within a file.

Egrep execution effect is similar to "GREP-E", the syntax and parameters used can refer to the GREP directive, and the difference between grep is the method of interpreting the string.

Egrep is interpreted with extended regular expression syntax, while grep is interpreted with the basic regular expression syntax, extended regular expression than basic Regular expression is more canonical.

+:o+ stands for 1 or more O

？ : O? Represents an empty or 1 O

|:egrep-n ' Gd|good ' data.txt find GD and good strings

(): Egrep-n ' G (la|oo) d ' data.txt find glad or good

() +:egrep ' A (xyz) +c ' Find a start, C ends with one or more xyz in the middle

Linux egrep Commands