Concatenation connected to find pipe behaves wierdly.

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

Replies are listed 'Best First'.
Re: Concatenation connected to find pipe behaves wierdly. by sfink (Deacon) on Jan 31, 2006 at 18:05 UTC
find is giving you a list of filenames terminated by newlines. So when you print qq($_), you're printing out a newline after your filename. So all your foo are belong to us... dammit... all of your foo end up just after a newline, aka the beginning of the next line. The quick fix is`find \| perl -lne "print qq($_) . q(foo)"` That will strip off the newline when reading each line in, and append a newline to the output of print.	[reply] [d/l]
Re^2: Concatenation connected to find pipe behaves wierdly. by blazar (Canon) on Feb 01, 2006 at 10:47 UTC
And while we're there we may also remind him not to unnecessarily quote all variables: `perl -lne "print $_ . 'foo'"` [download] Alternatives: interpolation, but not on a single variable: `qq(${_}foo)` - ugly, but `qq($_foo)` wouldn't work; introducing `-p`: `perl -lpe "$_.='foo'"` [download] ...	[reply] [d/l] [select]
Re: Concatenation connected to find pipe behaves wierdly. by chargrill (Parson) on Jan 31, 2006 at 18:29 UTC
`find` alone on a unix displays a help/usage message. `find` alone in a CMD window performs similarly. The following on a unix is a bit weird to me at first: `$ find . -name ".pl" \| perl -ne "print qq($_) . qw(foo)" foofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoof +oofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoof +oofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoof +oofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoof +oofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoof +oofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoo` [download] ... time passes, nodes are read, code is crafted, head is scratched, lightbulb illuminates, reply text is angrily deleted ...* I just went through the exercise of determining why I easily replicated tphyahoo's behavior, with an incorrect dissection of the differences between -n and -p, then I finally realized the same thing sfink did... `$ perl -ne 'print "$_ foo" ' perl.txt ./.cpan/build/DateTime-0.30/tools/leap_seconds_header.pl foo./.cpan/build/DateTime-TimeZone-0.40/t/check_datetime_version.pl` [download] Had you taken the TOP 'snippet' of output, you'd've VERY quickly seen the explanation :) --chargrill `$/ = q#(\w)# ; sub sig { print scalar reverse join ' ', @_ } + sig map { s$\$/\$/$\$2\$1$g && $_ } split( ' ', ",erckha rlPe erthnoa stJu +" );` [download]	[reply] [d/l] [select]
Re: Concatenation connected to find pipe behaves wierdly. by graff (Chancellor) on Feb 01, 2006 at 02:50 UTC
Another way to try would be: `find . -print0 \| perl -0pe "s/\0/foo\n/"` [download] Check perlrun for the "-0" option -- it's meant to take advantage of the "-print0" option on find, to avoid the possibility of getting screwed because a file name happens to include newline characters.	[reply] [d/l]
Re^2: Concatenation connected to find pipe behaves wierdly. by sfink (Deacon) on Feb 01, 2006 at 06:29 UTC
Or you could spell that `find . -print0 \| perl -l -0 -ne 'print $_ . "foo"'` [download] (Quotes this time are for a Unix shell.) It's a little wacky due to the order sensitivity of the command line arguments: `perl -0 -l -ne ...` would not work. But as graff said, see perlrun for the details.	[reply] [d/l] [select]