Thursday, April 30, 2009

perl introduction

perl -v

perl -e 'print 4;'

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

perl -we 'print "Two \n lines \n ";'

perl -we 'print "Mary \n";'

 

$greeeting is a scalar variable

 

vi spitback

+++++++++

#!/usr/bin/perl -w

print 'Enter a greeting: ';

$greeting =<>;

print $greeting;

++++++++++

 

chop removes the last character of the line

chomp removes onln \n new line.

$noun= $noun. 's';     #Pluralize noun by appending an 's' eg: cat will become cats

 

perl -e 'print 8 ** 3;'

perl -e '$num =2; $num **=4; print $num;'

perl -e 'print -7 ** 2'

 

perl -e ' $a =7; $b = $a++; print "$a, $b"; _;'

perl -e ' $a =7; $b = $++a; print "$a, $b"; _;'

 

examples:

perl -e '$x="lollipop"; $y=$x. $x; $y.="s\n"; print $y;'

output:

lollipoplollipops ( with newline)

 

example:

[swuser@poclab10 perl]$ cat meander.pl

#!/usr/bin/perl -w

print 'Please type an integer: ';

$num = <>;

chomp $num;

while ($num !=1) {

  print "$num\n ";

 

 if (($num %2 ) ==0)

     {$num /= 2;}

  else { $num *= 3; $num++;}

}


No comments:

Post a Comment