Re: How does $. work in one liner?

[eyepopslikeamosquito]

In your example, you don't need the $_. This will print lines 1 and 2 from the file test.txt:

perl -ne 'print if 1..2' test.txt

If you prefer to be more explicit:

perl -ne 'print if $. >= 1 && $. <= 2' test.txt

This type of question comes up often enough that I keep a list of one-liner references.

Update: See also:

• Flipin good, or a total flop?
• Behavior of Flip-Flop Operators
• The Scalar Range Operator
• perlop ("Range Operators" section)

[afoken]

In your example, you don't need the $_. This will print lines 1 and 2 from the file test.txt:

Assuming an OS that follows the POSIX spirit, this will also print the first two lines of a file, but probably without reading the entire file, and probably without starting an interpreter:

head -n 2 test.txt

(POSIX: head)

Alexander