Perl, BAT files and quoteless quoting.

As much as I hate DOS batch files (*.BAT), sometimes you are forced to use them for integration with other build tools.

One frustration I had with a BAT file was the normal Unix rules for quoting, using nested single and double quotes, don't work.

For example, in unix (or Cygwin), you can do

perl -e 'print "Hello\n";'

But DOS doesn't know about single quotes. If you try

perl -e "print 'Hello\n';"

You will get

Hello\n%

... the newline is ignored since you used single quotes. (My version of Cygwin displays the % meaning that the output does not have an EOL character).

The work around is to use the rarely used "qq" perl functions to do quote-less quoting. Thus the following example

perl -e "print qq{Hello\n};"

prints out the correct message with the newline.

Hello