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$ whatis uncompress

uncompress (1) - compress or expand files

Examples:

I like to copy the error_log as tmp_log and then compress and compress it as shown below:

# ls -l error_log

-rw-r--r-- 1 root root 2409238 2011-04-08 00:33 error_log

# du -sh error_log

2.4M error_log

# file error_log

error_log: ascii textg

# cp error_log tmp_log

# du -sh tmp_log

2.4M tmp_log

# file tmp_log

tmp_log: ascii textg

# compress tmp_log

# file tmp_log*g

tmp_log.Z: compressed data block compressed 16 bitsg

# ls -l tmp_log.Z

-rw-r--r-- 1 root root 231605 2011-04-08 01:00 tmp_log.Z

# du -sh tmp_log.Z

259K tmp_log.Z

# zcat tmp_log.Z | tail -10g

[Fri Apr 08 00:27:38 2011] [error] [client 173.51.166.200] Name "main::mycmd" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 29., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:28:19 2011] [error] [client 173.51.166.200] Name "main::arg" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 29., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:28:19 2011] [error] [client 173.51.166.200] Name "main::cmdargs" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 31., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:28:19 2011] [error] [client 173.51.166.200] Name "main::cmdbase" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 31., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:28:19 2011] [error] [client 173.51.166.200] Name "main::mycmd" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 29., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:33:43 2011] [error] [client 173.51.166.200] Name "main::arg" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 29., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:33:43 2011] [error] [client 173.51.166.200] Name "main::cmdargs" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 31., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:33:43 2011] [error] [client 173.51.166.200] Name "main::cmdbase" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 31., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:33:43 2011] [error] [client 173.51.166.200] Name "main::mycmd" used only once: possible typo at /var/apache2/2.2/cgi-bin/CH3.cgi line 29., referer: https://www.mywebuniversity.com/chapter-3.htmlg [Fri Apr 08 00:33:43 2011] [error] [client 173.51.166.200] Can't open the file! at /var/apache2/2.2/cgi-bin/CH3.cgi line 37., referer: https://www.mywebuniversity.com/chapter-3.htmlg

# compress -d tmp_log

# ls -l tmp_log

-rw-r--r-- 1 root root 2409238 2011-04-08 01:00 tmp_log

# file tmp_log

tmp_log: ascii textg

# tail -10 tmp_log

# file tmp_log

tmp_log: ascii textg

# du -sh tmp_log

2.4M tmp_log

# compress -f tmp_log

# ls -ld tmp_log*

-rw-r--r-- 1 root root 231605 2011-04-08 01:00 tmp_log.Z

# du -sh tmp_log.Z

259K tmp_log.Z

# file tmp_log.Z

tmp_log.Z: compressed data block compressed 16 bitsg

#zcat tmp_log.Z | head -5

[Fri Feb 18 20:43:52 2011] [warn] Init: Session Cache is not configured [hint: SSLSessionCache]g [Fri Feb 18 20:43:53 2011] [notice] Digest: generating secret for digest authentication ...g [Fri Feb 18 20:43:53 2011] [notice] Digest: doneg [Fri Feb 18 20:43:54 2011] [notice] Apache/2.2.16 (Unix) mod_ssl/2.2.16 OpenSSL/0.9.8o DAV/2 PHP/5.2.12 mod_fcgid/2.3.4 configured -- resuming normal operationsg [Fri Feb 18 21:07:57 2011] [warn] Init: Session Cache is not configured [hint: SSLSessionCache]g

# uncompress -d tmp_log.Z

# ls -l tmp_log.Z

-rw-r--r-- 1 root root 2409238 2011-04-08 01:00 tmp_log

# file tmp_log

tmp_log: ascii textg

# head -5 tmp_log

Please click on "man uncompress " to see the Manual Page for this command.