You can use the UNIX compress command to make a file smaller. Here is a worked example. I started by making a file called directory_list. I copied this file into another file called directory_list_save for future reference. Then I compressed the file called directory_list. This made the file much smaller and gave it a suffix of .Z. Finally, I compared the sizes of directory_list_save and directory_list.Z:
Tru64:/usr/users/oracle/andrew > ls -R $ORACLE_HOME > directory_list
Tru64:/usr/users/oracle/andrew > cp directory_list directory_list_save
Tru64:/usr/users/oracle/andrew > ls -l directory_list*
-rw-r--r-- 1 oracle dba 1971685 Feb 5 14:43 directory_list
-rw-r--r-- 1 oracle dba 1971685 Feb 5 14:43 directory_list_save
Tru64:/usr/users/oracle/andrew > compress directory_list
Tru64:/usr/users/oracle/andrew > ls -l directory_list*
-rw-r--r-- 1 oracle dba 558245 Feb 5 14:43 directory_list.Z
-rw-r--r-- 1 oracle dba 1971685 Feb 5 14:43 directory_list_save
Tru64:/usr/users/oracle/andrew >
You cannot read a file once you have compressed it as it is then in a different format. The purpose of compressing a file is to make it smaller so that it is easier to store or to send to somewhere else. I created the file on a Tru64 machine then decided to send it to a Solaris machine using scp.
Tru64:/usr/users/oracle/andrew > scp directory_list.Z \
> zge-mktred-ddb1:/export/home/oracle/andrew
The authenticity of host 'zge-mktred-ddb1 (10.80.1.116)' can't be established.
RSA key fingerprint is d6:59:ba:8d:c6:24:21:1b:91:c2:3b:c5:5a:5b:8c:f9.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'zge-mktred-ddb1,10.80.1.116' (RSA) to the list of known hosts.
Password:
directory_list.Z 100% 545KB 545.2KB/s 00:00
Tru64:/usr/users/oracle/andrew >
I read somewhere that you could compress a file on one platform and uncompress it on another. So, once it was on the Solaris machine, I uncompressed it. This proved that a file compressed on Tru64 could be uncompressed on Solaris. Notice how this removed the .Z suffix from the file name. Finally, I compressed the file again on the Solaris machine:
Solaris:/export/home/oracle/andrew > ls -l directory_list*
-rw-r--r-- 1 oracle dba 558245 Feb 5 14:49 directory_list.Z
Solaris:/export/home/oracle/andrew > uncompress directory_list.Z
Solaris:/export/home/oracle/andrew > ls -l directory_list*
-rw-r--r-- 1 oracle dba 1971685 Feb 5 14:49 directory_list
Solaris:/export/home/oracle/andrew > compress directory_list
Solaris:/export/home/oracle/andrew > ls -l directory_list*
-rw-r--r-- 1 oracle dba 558245 Feb 5 14:49 directory_list.Z
Solaris:/export/home/oracle/andrew >
Then I sent the compressed file back to the Tru64 machine:
Solaris:/export/home/oracle/andrew > scp directory_list.Z \
> sredsvr8:/usr/users/oracle/andrew
The authenticity of host 'sredsvr8 (10.80.1.32)' can't be established.
DSA key fingerprint is 10:c8:14:df:7a:bb:a7:56:1d:7d:f5:c7:76:ee:2a:33.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'sredsvr8,10.80.1.32' (DSA) to the list of known hosts.
oracle@sredsvr8's password:
directory_list.Z 100% |**********************************************************************************************************| 545 KB 00:00
Solaris:/export/home/oracle/andrew >
Once the file was back on the Tru64 machine, I uncompressed it to prove that you could compress a file on a Solaris machine then uncompress it on a Tru64 machine. Finally I used the diff command to check that the uncompressed file matched the backup copy, which I made at the start of the example:
Tru64:/usr/users/oracle/andrew > ls -l directory_list*
-rw-r--r-- 1 oracle dba 558245 Feb 5 15:15 directory_list.Z
-rw-r--r-- 1 oracle dba 1971685 Feb 5 14:43 directory_list_save
Tru64:/usr/users/oracle/andrew > uncompress directory_list.Z
Tru64:/usr/users/oracle/andrew > ls -l directory_list*
-rw-r--r-- 1 oracle dba 1971685 Feb 5 15:15 directory_list
-rw-r--r-- 1 oracle dba 1971685 Feb 5 14:43 directory_list_save
Tru64:/usr/users/oracle/andrew > diff directory_list directory_list_save
Tru64:/usr/users/oracle/andrew >
