This is not a recommended practice. Auto-shrinking the transaction log is likely to cause performance degradation on the server, as it will forever be growing and shrinking.
A better option would be to identify the correct size of the log, one that is large enough that it doesn't autogrow between log backups, but small enough that it doesn't unnecessarily consume a lot of disk space. Then leave it that way.
My guess is that Kaushik's scenario is that he has a transaction log that has gotten away from him and autogrown to a large size, but now he would like to get it back to a reasonable and stable size. In this case, he probably wants to shrink it once (off-hours, hopefully), and then let normal backup processes take over from there. In this circumstance, Eduardo's suggestion is the right one.
Cheers,
Matt
