compress misinformation

[eric stewart]

Here is my Q.
Has anyone gotten messages from compress that seem to be erronious?

I used find to see if there were any compressed files in a directory. THere were none.
I then ran compress -f on the files in that directory and compress said there were already compressed files?

Any ideas or is there a fix that I missed?

partial log of problem:

>find T1461A -type f -print|grep Z
>find T1461A -type f -exec compress -f {}\;
T1461A/MRBIG/NETOSTEO/DATABASE/abfappl.rb.Z: already has .Z suffix -- no change
T1461A/MRBIG/NETOSTEO/DATABASE/bsnova.rb.Z: already has .Z suffix -- no change
T1461A/MRBIG/NETOSTEO/DATABASE/copyvt.out.Z: already has .Z suffix -- no change

[Vikas Khator]

Hi ,

Let me try explaining it .

First time when you do a find you have no Z files so you do not get any.

Next find finds a file for e.g. abc and sends this to compression routine . The compression routine creates a new file abc.Z .

As find continues to execute further it also comes across a file abc.Z ( created earlier from a file abc ) and complains .

Try following and see if it fixes your problem :

find T1416A -type f |xargs compress

[Bruce Regittko_1]

Hi,

I suspect what happened is that find found the first file and compressed it. Then find found the "new" file and tried to compress it again only now it had the .Z extention.

The man page for find(1) suggests using a + instead of a ; to punctuate the command. This will allow the -exec command to operate on the aggregated set of pathnames and execute on the set instead of one file at a time. This will also greatly improve performance since there will only be one compress command generated.

--Bruce

[Bruce Regittko_1]

Hi again,

I've never used the + before in a find command and just now found it rather flakey. In order for it to work correctly, I had to put a null argument before the {}. Thus,

find /dir -name "whatever" -exec command -opt "" {} \+

Without the "", -opt is ignored. I wonder if this is an undocumented "feature" or a bug.

--Bruce

[eric stewart]

vikas,
if your theory is correct, how come it does not happen on every file?
TX
Eric