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80

Error Messages

• This error message is no good:

     if (-e $dst) {
       die "Can't continue because a file has target's dir name\n"
         unless -d _;
     } ...

• Suppose the program dies in the middle and says

     Can't continue because a file has target's dir name

• Which file!?!?!

• Even if you somehow understand this, it doesn't help.

• Now you get to go groveling over the target directory looking for the bad file.

• Error messages should describe the cause of the problem

     if (-e $dst) {
       die "File $dst exists but is not a directory" unless -d _
     } ...

• Now it says

     File c:/temp/perl-5.7.1/lib/CGI/eg/crash.cgi exists but is not
     a directory at xcopy.pl line 25

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Copyright © 2002 M. J. Dominus