perlrun: -a implicitly sets -n

1nickt has asked for the wisdom of the Perl Monks concerning the following question:

Hi all, in perlrun under the documentation for the -a switch it states:

-a implicitly sets -n.
[download]

My testing seems to show this is not the case:

$ cat test.dat 
foo bar
baz quux
$ perl -wMstrict -M5.010 -ane 'say $F[0]' test.dat 
foo
baz
$ perl -wMstrict -M5.010 -ae 'say $F[0]' test.dat 
Variable "@F" is not imported at -e line 1.
Global symbol "@F" requires explicit package name at -e line 1.
Execution of -e aborted due to compilation errors.
[download]

Am I missing something?

The way forward always starts with a minimal test.

Comment on perlrun: -a implicitly sets -n Select or Download Code

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Re: perlrun: -a implicitly sets -n by stevieb (Canon) on Jul 30, 2015 at 23:21 UTC
Update: I just looked, and the first version I can find that this was introduced is in `v5.20.0`, here, so you probably are on `v5.18.0` or earlier. Which version of perl, and in which version of `perlrun` did you glean that from? I'm on `v5.22.0`. `steve@spek ~/scratch $ perl -wMstrict -M5.010 -ae 'say $F[0]' test.dat foo baz` [download]	[reply] [d/l] [select]
Re^2: perlrun: -a implicitly sets -n by 1nickt (Canon) on Jul 30, 2015 at 23:41 UTC
Thanks stevieb and browseruk, indeed, I am on 5.16.0, and the perlrun I consulted was the on-line version. I'll submit a patch with a note. The way forward always starts with a minimal test.	[reply] [d/l]
Re^3: perlrun: -a implicitly sets -n by stevieb (Canon) on Jul 30, 2015 at 23:55 UTC
Hey 1nickt, the online version (by default) is `v5.22.0`. The `v5.16.0` version doesn't have that info, so I don't know if a patch is necessary. Can you post a link to the version of `perlrun` you found this in, just to be sure?	[reply] [d/l] [select]
Re^4: perlrun: -a implicitly sets -n by 1nickt (Canon) on Jul 31, 2015 at 00:20 UTC
Re^5: perlrun: -a implicitly sets -n by stevieb (Canon) on Jul 31, 2015 at 00:50 UTC
Some notes below your chosen depth have not been shown here
Re: perlrun: -a implicitly sets -n by BrowserUk (Patriarch) on Jul 30, 2015 at 23:27 UTC
It seems that feature was added somewhere between versions 5.18 & 5.20: `C:\test>\perl5.18\perl\bin\perl.exe -mstrict -waE"say @F" counts C:\test>\perl5.18\perl\bin\perl.exe -mstrict -wanE"say @F" counts 00000018801880 C:\test>\Perl5.20\bin\perl.exe -mstrict -wanE"say @F" counts 00000018801880 C:\test>\Perl5.20\bin\perl.exe -mstrict -waE"say @F" counts 00000018801880` [download] Anyone got any experience of this phone's predecessor? With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :) In the absence of evidence, opinion is indistinguishable from prejudice. I'm with torvalds on this Agile (and TDD) debunked I told'em LLVM was the way to go. But did they listen!	[reply] [d/l]
Re^2: perlrun: -a implicitly sets -n by stevieb (Canon) on Jul 30, 2015 at 23:35 UTC
Yep, I did some research (and updated my first post). It became effective during 5.19 (officially available in 5.20).	[reply]