Linux Study notes Sixth week first Class (March 12)

9.1 Regular Introduction on _grep

Egrep is the extension of grep, with all grep functions;

grep is used to filter the keywords;

-R Traverse All subdirectories

-V to reverse, meaning that in addition to the keywords in the row, the other lines show up;

9.2 grep in

' 0-9 ' means any number from 0 to 9;

' "^0-9" means any number other than 0 to 9;

' ^# ' denotes lines beginning with #;

^ Put in brackets inside ' [^ keywords] ', indicating non;

^ Put in front of the keyword ' ^ keyword ' to denote the beginning of the keyword;

9.3 grep under

' R.O ', the character "." Represents any one character;

' R*o ', the character "*" denotes any n characters;

'. * ' denotes all characters;

\ de-ideographic character;

{} curly braces denote the repeating range of the preceding character;

' O\{2\} ' represents two o;

GREP-E equivalent to Egrep;

grep ' o\{2\} ' passwd equivalent to Egrep ' o{2} ' passwd or grep-e ' o{2} ' passwd;

+ denotes 1 or more occurrences of the preceding character;

？ Represents 0 or 1 times the preceding character; ' O? T ' means t or ot;

| Express or;

() represents a combined string;

Extended

Filter all the lines in the *.php document that contain eval in a directory

Grep-r--include= "*.php" ' eval '/data/

Linux Study notes Sixth week first Class (March 12)