Metacharacters

^ matches at start of line
$ matches at end of line
. matches any single character except newline (\n)
* matches zero or more of previous character or group
? matches zero or more of previous character or group
+ matches one or more of previous character or group
.* as many characters as you like


Program to illustrate above regular expressions

#!/usr/bin/perl

#should be
while(STDIN)
{

if(/^hello/g)
{
print("hello is at the beginning \n")
}

if(/Bye$/g)
{
print("Bye is at the end \n")
}


if(/A?/g)
{
print("This has zero and one A with regular Expression'?'\n")
}

if(/A*/g)
{
print("This has zero and one A with regular Expression '*' \n")
}

if(/A+/g)
{
print("This has one or more A \n")
}

}