Long-Term Learning

Learn efficiently and remember over time.

Start Long-Term Learning

Get personalized study reminders at intervals optimized for better retention.
Track your progress on this set by creating a folder
Or add to an existing folder

Add this set to a folder

  • $&

    String matched by last pattern match.


    String preceding what was matched in last pattern match.


    String following what was matched in last pattern match.


    Default input and pattern-searching space.


    Current line number on the filehandle last read.


    Input record separator, newline by default. You can set this to an entire file by "local $/".


    The output record separator for the print operator. You can set this to "\n" instead of adding that to every print statement.


    The output field separator for the print operator.


    The output field separator for the print operator when array is enclosed in double quotes, i.e. "@animals".


    PID of this perl script.


    Status returned by system command or `` command.


    Contains name of perl script.


    Current value of errno.


    System environment variables


    Args passed into perl program.


    Args passed to subroutine.


    Subpatterns extracted from regular expressions.


    Perl syntax error trapped by eval



    Please allow access to your computer’s microphone to use Voice Recording.

    Having trouble? Click here for help.

    We can’t access your microphone!

    Click the icon above to update your browser permissions above and try again


    Reload the page to try again!


    Press Cmd-0 to reset your zoom

    Press Ctrl-0 to reset your zoom

    It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

    Please upgrade Flash or install Chrome
    to use Voice Recording.

    For more help, see our troubleshooting page.

    Your microphone is muted

    For help fixing this issue, see this FAQ.

    Star this term

    You can study starred terms together

    NEW! Voice Recording

    This is a Plus feature