Hi supriyoch_2008,

A Perl programmer developing a script without use strict is a bit like a trapeze artist practising a new trick without a safety net. In other words, it’s a Bad Idea (unless you enjoy all-night debugging sessions). But it’s your call.

However, I think you may have some misconceptions about what strict does:

I have noticed that "use strict;" sometimes does not give me the correct result from my script and the cmd shows a large number of warnings. Without the "use strict;" line in my script, I often get the desired result.

This is simply not possible! First, use strict never issues warnings, it generates errors which cause the script to abort immediately they occur. Second, if the script runs without errors, then the presence of use strict does not change the way it runs in any way.

use strict is actually three pragmata rolled into one:

1. use strict 'refs';

   This prevents you from using symbolic references, and since you probably don’t use them anyway, it won’t have much impact on your code.

2. use strict 'subs';

   Consider the difference between these snippets:

   18:18 >perl -E "sub foo { return 'bar'; } $y = foo; say $y;"
   bar
   
   18:19 >perl -E "$y = foo; sub foo { return 'bar'; } say $y;"
   foo
   
   18:20 >
   [download]

   In the second, “foo” is treated as a string, not a subroutine name, so the output is not what you wanted. use strict 'subs' prevents this by forcing you to either declare your subroutines before calling them, or call them explicitly with parentheses. This is a Good Thing.

3. use strict 'vars';

   This is the one that makes you declare each variable with my (or our) the first time it is used. More typing? Sure, but think how much debugging time it will save you down the track when you have a variable named opensesame which you later write as openseseme by mistake!

See strict and then recite The strictures, according to Seuss as needed. :-)

Hope that helps,

I avoid using "use strict;" in the script because "my" has to placed before every scalar and array variable. Moreover, I have noticed that "use strict;" sometimes does not give me the correct result from my script and the cmd shows a large number of warnings. Without the "use strict;" line in my script, I often get the desired result. That is why I avoid "use strict;" although I know that it detects the flaws in a script.