How to find out a compressed file inside a script ?

balakrishnan has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: How to find out a compressed file inside a script ? by moritz (Cardinal) on Feb 19, 2009 at 15:34 UTC
You could check for a magic number, for example by using File::MMagic or similar modules. Or you could just try to decode it, and treat it as uncompressed if the decoding fails.	[reply]
Re^2: How to find out a compressed file inside a script ? by Bloodnok (Vicar) on Feb 19, 2009 at 15:54 UTC
...or, if on *NIX, first use `magic(1)` - the compression method just might be in `/etc/magic` ... you never know:-) A user level that continues to overstate my experience :-))	[reply] [d/l] [select]
Re: How to find out a compressed file inside a script ? by lakshmananindia (Chaplain) on Feb 20, 2009 at 04:43 UTC
Once I got a chance to read Archive::Tar module. There is a function named _read_tar. In that function they will read first 512 bytes from the file. They will check whether it contains the GZIP magic number is there in the 512 bytes. The magic number is a constant defined in Constant.pm inside the Tar directory I suggest you to go through that module. I feel this information can help you	[reply]
Re: How to find out a compressed file inside a script ? by balakrishnan (Monk) on Feb 20, 2009 at 10:49 UTC
UPDATE : Finally i got it by, `perl -MFile::Type -le 'print File::Type->new->checktype_filename("text +.gz")'` [download] Thanks to the monks.	[reply] [d/l]
Re: How to find out a compressed file inside a script ? by dwm042 (Priest) on Feb 19, 2009 at 17:08 UTC
On the Unix command line, I tend to use 'file': `file *.zip applepie.zip: ZIP archive keylime.zip: ZIP archive` [download] Which is pretty much the same technique (relying on a magic number) as moritz and Bloodnok are advocating.	[reply] [d/l]
Re: How to find out a compressed file inside a script ? by prasadbabu (Prior) on Feb 19, 2009 at 15:35 UTC
Hi balakrishnan, try the below code and add your extensions as per your requirement, `$filename =~ /\.(zip\|gzip\|txt)$/i` Also you can use File::Basename to get the file extensions exactly. update: Sorry I misread the question, forgot to see 'dont' Prasad	[reply] [d/l]