in reply to Re: modifying a line in a file with some restrictions
in thread modifying a line in a file with some restrictions

attempting to slurp the entire file ($/="")
No, he's reading it in paragraph mode. See perlvar. Update: That is, of course, he would be reading it in paragraph mode if he had opened it for reading.
Replacing everything in the file (if the file ends with a newline)
No, he is only replacing the first line of the paragraph.

Makeshifts last the longest.

  • Comment on Re^2: modifying a line in a file with some restrictions

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Re: Re^2: modifying a line in a file with some restrictions
by BrowserUk (Patriarch) on Jan 14, 2003 at 09:31 UTC

    Good point about the paragraph mode, but he's not reading anything from a file opened write-only.

    However, if he was reading a paragraph, it wouldn't be the first line of the paragraph he would be replacing.

    The text replace would be the last line of the paragraph plus the two or more newlines that delimited the paragraph. Somehow I doubt that this was his intention, but the point is mute until he manages to read something in.

    Seems we both need to read perlop, and possibly perlre as well ....

    Examine what is said, not who speaks.

    The 7th Rule of perl club is -- pearl clubs are easily damaged. Use a diamond club instead.

[reply]
      The text replace would be the last line of the paragraph plus the two or more newlines that delimited the paragraph.
      Good catch about the (one!) newline, but I'm puzzled at how you arrive at other the conclusion. He is using /m which doesn't make the dot match newlines. 
      $ perl -le'(join "\n", qw(foo bar baz)) =~ /(.*\n)/m && print $1'
foo

$ # note the embedded newline

      [download]
      Yes, perlre is a good suggestion. ;-)

      Makeshifts last the longest.

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        Usual way, I tried it:). I've never had occasion to make use of paragraph mode, hence my mistaking it for slurp mode, so I tried it out to see what the effect was and the code below was my test suite.

        Test code

        Read more... (4 kB)

        output

        Read more... (3 kB)

        Examine what is said, not who speaks.

        The 7th Rule of perl club is -- pearl clubs are easily damaged. Use a diamond club instead.

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[d/l]
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