PERL Class Lesson 2
FIRST SCRIPT

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FIRST SCRIPT

- In SSH terminal type:  vim first.pl  and hit Enter



- Once in vim, create the following script


The first line  #!/usr/bin/env perl  is called the "SHEBANG"
It tells the computer what language you are about to start talking in and where it can find the so called dictionary to understand what you are going to tell it to do.

Then next line starts with a pound sign  #  and anything following that is a  comment  which means it is there for the programmer and basically does nothing but remind or explain whatever you want to put there.

The  use strict  tells the computer that it must follow strict rules, nothing just slides on by.

The  use warnings  tells the computer that it must tell us if there is an error in our coding.

Every line must end in a semi-colon      ;      that tells the computer that we are done with that line of code and it needs to move on to the next line of code and read that one as a seperate command.

The  print  command tells the computer to display or print the following words or numbers out onto the screen when the program is run.

- Now save the script (wq  first.pl  )
- Then in the SSH Shell we change the permissions so it will work for us (chmod 755 first.pl)
- And now we run it to test if everything is coded correctly (  ./first.pl  )
- to run anything in perl you have to put a dot   .   and a slash  /  in front of it and then hit ENTER

When Trying To Run  first.pl  Notice How An  Error  Is Displayed
Can't locate warning.pm in @INC (@INC contains:
/usr/lib/perl5/5.8.8/x86_64-linux
/usr/lib/perl5/5.8.8
/usr/lib/perl5/site_perl/5.8.8/x86_64-linux
/usr/lib/perl5/site_perl/5.8.8
/usr/lib/perl5/site_perl/5.8.5
/usr/lib/perl5/site_perl/5.8.4
/usr/lib/perl5/site_perl/5.8.3
/usr/lib/perl5/site_perl/5.6.2
/usr/lib/perl5/site_perl .) at ./first.pl line 4.
BEGIN failed--compilation aborted at ./first.pl line 4.



-  Warning.pm  can't be found because it is suppose to be  use warnings  with an   s   at the end

- Fix the script making sure you have  use warnings  with an  s  on the end of it


- Run it again and this time you should see  'words'  butted right up in front of your location or pwd




Congratulations!!!! You just got the computer to output something.

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