Don Coyote has asked for the wisdom of the Perl Monks concerning the following question:

After rolling a FORMAT oneliner! :) I echo'd this into a file. Now my laziness is starting to niggle and I decide it is about time to edit in place those semicolons into newlines rather than doing this manually.

After clobbering the file a number of times. I could not get a 'simple' s/// or tr/// to operate on a perl -ni -e command. I eventually split the looping stdin file at the semi-colons and joined with newlines, and this was fine. But I wonder why I wasn't able to s/// or y/// on a looping file? some examples:

file to which one-liner echo'd

#! \usr\bin\perl

use strict;
use warnings;

"my $fs = q!.\funkisym.pm!;open(FUNKISYM, q(>),qq($fs)); my $flashbang
+ = q{#! \usr\bin\perl};my $pra = q!use strict;!; my $pra2 = q!use war
+nings;!;my @fstr = (q(format  FUNKISYM = ),q(@).q(<) x 16,q($flashban
+g).qq(\n),q(@).q(<) x 11,q($pra),q(@).q(<) x 13,q($pra2),qq(.\n));eva
+l(join($/,@fstr));select FUNKISYM;write;exec(qq!notepad\.exe $fs!);"

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attempted commands which either clobbered file and/or produced bareword deaths on tr///

perl -n -i.bak -e "tr/;/\n/;" .\funkisym.pm
perl -n -i.bak -e "y/\Q;\E/\n/;" .\funkisym.pm
perl -n -i.bak -e "s/(;)/$1\n/g;" .\funkisym.pm

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I tried variations further to those shown, and settled for the following solution;

perl -ni.bak -e "my @text = split(q{;});print join(qq(;$/), @text);" .
+\funkisym.pm"

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Please can you suggest what I may be assuming incorrectly, in relation to this problem?

Replies are listed 'Best First'.
Re: s/// + tr/// when perl -ni -e on semi-colons in one liners echoed to files
by Anonymous Monk on Nov 18, 2012 at 12:37 UTC

    Well, -n doesn't print, but -p does print :) 

    $ perl -le " print qq{a;b;c;d} "
a;b;c;d

$ perl -le " print qq{a;b;c;d} " | perl -ne " tr/;/\n/ ; "

$ perl -le " print qq{a;b;c;d} " | perl -pe " tr/;/\n/ ; "
a
b
c
d

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[d/l]

      ok, thanks for the quick reply. It seems I was assuming -i edits 'in place'. And -n / -p only controlled if STDOUT was printed to or not.(i think it was SED).

      Just trying to analyse more complex stuff while tripping over the 'simple' stuff...

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Re: s/// + tr/// when perl -ni -e on semi-colons in one liners echoed to files
by aitap (Curate) on Nov 18, 2012 at 13:06 UTC
    You could feed this string to perltidy: 
    $ perltidy
my $fs = q!.\funkisym.pm!;open(FUNKISYM, q(>),qq($fs)); my $flashbang 
+= q{#! \usr\bin\perl};my $pra = q!use strict;!; my $pra2 = q!use warn
+ings;!;my @fstr = (q(format  FUNKISYM = ),q(@).q(<) x 16,q($flashbang
+).qq(\n),q(@).q(<) x 11,q($pra),q(@).q(<) x 13,q($pra2),qq(.\n));eval
+(join($/,@fstr));select FUNKISYM;write;exec(qq!notepad\.exe $fs!);
^D
my $fs = q!.\funkisym.pm!;
open( FUNKISYM, q(>), qq($fs) );
my $flashbang = q{#! \usr\bin\perl};
my $pra       = q!use strict;!;
my $pra2      = q!use warnings;!;
my @fstr      = (
    q(format  FUNKISYM = ),
    q(@) . q(<) x 16,
    q($flashbang) . qq(\n),
    q(@) . q(<) x 11,
    q($pra),
    q(@) . q(<) x 13,
    q($pra2),
    qq(.\n)
);
eval( join( $/, @fstr ) );
select FUNKISYM;
write;
exec(qq!notepad\.exe $fs!);

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    (in this example ^D is used to end the input data; in Windows you'll need to use ^Z)
    Edit: correct input data and usage example
    Sorry if my advice was wrong.
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[d/l]
Re: s/// + tr/// when perl -ni -e on semi-colons in one liners echoed to files
by Anonymous Monk on Nov 18, 2012 at 12:31 UTC
[reply]

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