tulic , i tried that but the else block is not executing. i can explain the behavior of the cisco device if a particular command is not present... if i telnet into cisco device it will show as 

2960#

[download]
here at this prompt i want to check one command i.e 
2960#sh run | in ntp

[download]
if the configuration is not present then it will show as same 
2960#

[download]
so at this time the in array @output doesn't contain anything but i dont know why the else block is not executing

In reply to Re^2: Empty string checking in output by Kumar Mantri
in thread Empty string checking in output by Kumar Mantri

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