Re^2: How does $. work in one liner?

There's nothing special about one-liners, not even the options which can be present in the shebang. The -n option on the other hand can make using $. a little more tricky, as it will not be reset from one file to the other if you are processing several at once. You can force it to be reset by closing the file handle as shown in eof, but personally at this point I would consider turning the one-liner into a .pl file. The $. issue is still true in a file script when using <>, but I haven't often seen it used to read from files rather than STDIN outside of a one-liner.

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Re^3: How does $. work in one liner? -- it does not reset automatically
by Discipulus (Canon) on May 29, 2016 at 20:07 UTC

Eily

elevenfly

$.

He gave you the definition, i'll add an example. Given a.txt and b.txt as following:

#cat a.txt
a file line 1
a file line 2
a file line 3

#cat b.txt
b file line 1
b file line 2
b file line 3
[download]

$.

..

#perl -ne "print if 1..2" a.txt b.txt
a file line 1
a file line 2
[download]

$.

close

-n

ARGV

But if you use the right idiom close ARGV if eof everything runs as expected: $. is reset by the explicit close that happens only if eof is encounterd:

#perl -ne "print if 1..2; close ARGV if eof" a.txt b.txt
a file line 1
a file line 2
b file line 1
b file line 2
[download]

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