If you want to know how to pass strings that look like variable names to the shell via backticks, you need to quote the special chars: 
my $res = `echo \$JAVA_HOME`;

[download]
To be completely thorough and pedantic, you can also use the qx operator with single quotes: 
my $res = qx'echo $JAVA_HOME';

[download]

-QM
--
Quantum Mechanics: The dreams stuff is made of

In reply to Re^2: taking an output in a variable by QM
in thread taking an output in a variable by s_gaurav1091

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