Get original file size of zipped file

Shell Programming and Scripting
1

Hi,

I have a process which creates files and gzip all the files.
Next day, i need to get the file sizes ( before zip size ) of all the gzipped files. Is there any way i can get the original file sizes of gzipped files.
Gunzipping the files, getting the file size and gzipping again is not the approach i am looking for?
I appreciate your responses.

Thanks in Advance.

2

17 seconds of grubbing around in man gunzip found gunzip -l

This even appears to work with streams, much to my surprise.

3

If you use the -l switch, it lists the files and both their compressed and uncompressed sizes:

gzip -l file.txt.gz 
compressed        uncompressed  ratio uncompressed_name
      81                      68          20.6%      file.txt

Hope this helps.

---------- Post updated at 10:03 AM ---------- Previous update was at 10:02 AM ----------

17 seconds, damn, took me 20... coffee hasn't kicked in yet.

5

Are you sure, Jim?

$ cat vectortop.png | gzip > vectortop.png.gz
$ gunzip -l vectortop.png.gz
         compressed        uncompressed  ratio uncompressed_name
               4360                4337  -0.1% vectortop.png
$

The 'cat' is to make sure it's not doing anything sneaky like running fstat on /dev/stdin.

---------- Post updated at 09:46 AM ---------- Previous update was at 09:14 AM ----------

yet again, working on streams:

$ gunzip -l < vectortop.png.gz
         compressed        uncompressed  ratio uncompressed_name
               4360                4337  -0.1% stdout

The limit seems to be that the compressed file has to be a file, not a stream, for the final size to be known. Maybe it has to seek to the end, impossible in a stream.

$ cat vectortop.png.gz | gunzip -l 
         compressed        uncompressed  ratio uncompressed_name
                 -1                  -1   0.0% stdout
$
6

Thanks All.

Solutions worked

7

Solution worked. Its displays the size in bytes.
How can i convert these sizes into MB?

8

Divide by one million.

gunzip -l whatever.gz | awk 'NR==2 { print sprintf("%.1f MB", $2/(1000*1000)); exit }'