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Read 20 lines when pressing n for next
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Read 20 lines when pressing n for next s9uzaa 04-29-2008
Posted by s9uzaa on April 29, 2008, 9:21 pm
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 Hi,
I would like to write a perl script with the following criteria match.
1. open any text file taken the name from the command line.
2. read top 20 lines and stops, then
3. ask to press letter "n or p" (for next/previous) to print next or
previous 20 lines.
would appreciate any kind of help.
4. must have subroutine used.

thanks

Posted by Jürgen Exner on April 29, 2008, 9:48 pm
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 s9uzaa@gmail.com wrote:
>I would like to write a perl script with the following criteria match.
>1. open any text file

perldoc -f open

>taken the name from the command line.

perldoc perlvar and check for '@ARGV'

>2. read top 20 lines and stops, then

perldoc perlsyn and check for 'for'. However given the next requirement
the algorithm becomes a lot easier if you slurp in the whole file into
an array. If you read 20 line chunks then you need to seek forward and
backward all the time which is a real pain. In an array you just move
your current index.

>3. ask to press letter "n or p" (for next/previous)

perldoc -q single

>to print next or previous 20 lines.
> would appreciate any kind of help.

Maybe you should ask your tutor/teacher?

>4. must have subroutine used.

perldoc perlsub

jue

Posted by A. Sinan Unur on April 29, 2008, 9:48 pm
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s9uzaa@gmail.com wrote in news:37b9eb38-e188-4dc2-b3a7-
5f09cc3b81ea@a70g2000hsh.googlegroups.com:

> I would like to write a perl script with the following criteria match.

Give it a shot. Then post any questions you might encounter (please read
the posting guidelines first).

> 1. open any text file taken the name from the command line.
> 2. read top 20 lines and stops, then
> 3. ask to press letter "n or p" (for next/previous) to print next or
> previous 20 lines.
> would appreciate any kind of help.
> 4. must have subroutine used.

Look up $. in perldoc perlvar

Sinan

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comp.lang.perl.misc guidelines on the WWW:
http://www.rehabitation.com/clpmisc/

Posted by Chris Mattern on April 30, 2008, 11:49 am
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> s9uzaa@gmail.com wrote in news:37b9eb38-e188-4dc2-b3a7-
> 5f09cc3b81ea@a70g2000hsh.googlegroups.com:
>
>> I would like to write a perl script with the following criteria match.
>
> Give it a shot. Then post any questions you might encounter (please read
> the posting guidelines first).
>
>> 1. open any text file taken the name from the command line.
>> 2. read top 20 lines and stops, then
>> 3. ask to press letter "n or p" (for next/previous) to print next or
>> previous 20 lines.
>> would appreciate any kind of help.
>> 4. must have subroutine used.
>
> Look up $. in perldoc perlvar
>
I got $5 that says this is homework. "must have subroutine used" is
a dead giveaway.

--
Christopher Mattern

NOTICE
Thank you for noticing this new notice
Your noticing it has been noted
And will be reported to the authorities

Posted by Jürgen Exner on April 30, 2008, 12:46 pm
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>> s9uzaa@gmail.com wrote in news:37b9eb38-e188-4dc2-b3a7-
>>> 4. must have subroutine used.
>>
>> Look up $. in perldoc perlvar
>>
>I got $5 that says this is homework. "must have subroutine used" is
>a dead giveaway.

Absolutely agree. However, the tutor isn't that smart, either.

A sub
        sub do_nothing{};

that is called somewhere in the program would already fulfill that
requirement. Probably not what he had in mind but apparently he couldn't
come up with a more appropriate one.

jue

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