#14 Regex - Regular Expression || MAC Changer || Python for Hacking

 Python for Hacking

MAC Changer

Algorithm Step 2

Step2: Read the mac address from output.

To read the MAC Address from output we use RegEx method.

RegEx

• A RegEx or Regular Expression, is a sequence of characters that forms a search pattern.
• RegEx can be used to check if a string contains the specified search pattern.
• Uses rules to match the pattern

Rules

•  /  Escape special characters
•  .  Matches any characters
•  ^  Matches beginning of string
•  $  Matches end of string
•  [5b-d]  Matches any chars '5', 'b', 'c' or 'd'
•  [^a-c6]  Matches any char except 'a', 'b', 'c' or '6'
•  R|S  Matches either regex R or regex S
•  ()  Creates a capture group and indicates precedence
•  *  0 or more (append ? for non-greedy)
•  +  1 or more (append ? for non-greedy)
•  ?  0 or 1 (append ? for non-greedy)
•  {m}  exactly mm occurrences
•  {m, n}  from m to n. m defaults to 0, n to infinity
•  {m, n}?  from m to n, as few as possible
•  \A start of string
•  \b  matches empty string at word boundary (between \w and \W)
•  \B  matches empty string not at word boundary
•  \d  digit
•  \D  non-digit
•  \s  whitespace: [ \t\n\r\f\v]
•  \S  non-whitespace
•  \w  alphanumeric: [0-9a-zA-Z_]
•  \W  non-alphanumeric
•  \Z  end of string
•  \g<id>  matches a previously defined group
•   (?iLmsux)  matches empty string, sets re.X flags
•  (?:...)  non-capturing version of regular parentheses
•  (?P...)  matches whatever matched previously named group
•  (?P=)  digit
•  (?#...)  a comment; ignored
•  (?=...)  lookahead assertion: matches without consuming
•  (?!...)  negative lookahead assertion
•  (?<=...)  lookbehind assertion: matches if preceded
•  (?<!...)  negative lookbehind assertion
•  (?(id)yes|no)  match 'yes' if group 'id' matched, else 'no'

In our case we need to find MAC Address from the ifconfig result for that we use the rule given below.

\w\w:\w\w:\w\w:\w\w:\w\w:\w\w