· Offer Kaye > Perl > Reverse Paragraphs
Explanation of 'Reverse Paragraphs' Perl oneliner
Here is the code again: perl -00e'print reverse<>'
"reverse<>" - since reverse is in the list context provided by "print", it will return a list value consisting of the elements
of <> (the input paragraphs) in the opposite order.
"print" - will print the list returned by "reverse".
"-00" - generally, the command line switch "-0[digits]" specifies the input record separator ($/) as an octal number.
Specifically, the special value 00 will cause Perl to slurp files in paragraph mode. Note that "paragraph" here means one or
more consecutive lines matching /^$/ (i.e. a completly blank line) seperate the paragraphs from one another.
Usage Example
Given an input file called "example" with the contents:
a
b
c
d
Then running the following from the command line:
perl -00e'print reverse<>' example
will print to STDOUT the following four lines:
c
d
a
b
Note that there was no empty line between "d" and "a" because there was no empty line following "d".
Offer Kaye /
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Last Modified: Thu Jul 15 23:04:09 2004
