Perl e Substitution Modifier [evaluate]

Perl e Substitution Modifier

The e modifier is used if you want the right-hand side of the substitution to be evaluated as code, instead of being treated as a string. For example,

s/$(\w+)//e;

That will replace anything that looks like a Perl scalar variable with the contents of that variable. This is extremely useful for embedding values in a text file.
Let us look at this example more closely:

Regular Expressions

1) The user is referring to a variable name $money — The user is referring to a variable name $money. so the substitution must evaluate this as code instead of as a string.

2) This line of code will do the substitution — This line of code will do the substitution

3) Matches the dollar sign in before money — Matches the dollar sign in before money

4) matches any word that comes after the dollar sign. — matches any word that comes after the dollar sign. The brackets tell the Perl program to remember what matched the \w+ and stores that in the variable $l.

5) refers to the first item in parentheses in a matching string — refers to the first item in parentheses in a matching string

6) makes the item a scalar variable — makes the item a scalar variable

7) tells the Perl program to treat the resulting string as a Perl variable, not a literal string — tells the Perl program to treat the resulting string as a Perl variable, not a literal string

8) The result is the Perl variable money — The result is the Perl variable money