Monomachus wrote:
> Ok here I am at the 9th chapter ...
> But here is a thing that isn't working at my computer :
>
> Exercices:
>
> Write a program to add a copyright line to all of your exercise answers so
> far, by placing a line such as:
>
> ## Copyright (C) 20XX by Yours Truly
>
>
> Place it in the file immediately after the "shebang" line. You should edit
> the files "in place" and keep a backup. Presume that the program will be
> invoked with the filenames to edit on the command line.
>
> [15] Extra extra credit exercise: Modify the previous program so it doesn't
> edit the files that contain the copyright line. Hint: You might need to know
> that the name of the file being read by the diamond operator is in $ARGV
>
> first program was:
>
> $^I = ".bak"; # make backups
> while (<>) {
> if (/^#!/) { # is it the shebang line?
> $_ .= "## Copyright (C) 20XX by Yours Truly\n";
> }
> }
>
> and that was perfectly working at my computer; but the second one:
That won't work unless you print the current line.
> my %do_these;
> foreach (@ARGV) {
> $do_these{$_} = 1;
> }
> while (<>) {
> if (/^## Copyright/) {
> delete $do_these{$ARGV};
> }
> }
> @ARGV = sort keys %do_these;
> $^I = ".bak"; # make backups
> while (<>) {
> if (/^#!/) { # is it the shebang line?
> $_ .= "## Copyright (c) 20XX by Yours Truly\n";
> }
> }
>
>
> Isn't working (in Windows)... I need to push Ctrl-C to stop the proccess.
That looks like it should work, if you add print to print out the current line.
> And one more thing:
> why can't I just print smth like:
>
> $^I = ".bak"; # make backups
> while (<>) {
> unless (/^## Copyright/){
> if (/^#!/) { # is it the shebang line?
> $_ .= "## Copyright (C) 20XX by Yours Truly\n";
> }
> print;
> }
> }
That won't work because you are testing for /^## Copyright/ first but that
line comes after the /^#!/ line.
John
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fulfillment
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