CPU Usage

This summary is not available. Please click here to view the post.

General Performance

This summary is not available. Please click here to view the post.

Linux Archive Tools (tar, star, gzip, bzip2, zip, cpio)

This article discusses the archiving tools available in Linux, with specific reference to the information needed for the RHCSA EX200 and RHCE EX300 certification exams.
Remember, the exams are hands-on, so it doesn't matter which method you use to achieve the result, so long as the end product is correct.

• tar
• star
• gzip
• bzip2
• zip
• cpio

All the commands in this article have many options in addition to the basic ones being used here. Please check the man pages for each command. The examples will use the following files.

mkdir -p /tmp/test-dir/subdir1
mkdir -p /tmp/test-dir/subdir2
mkdir -p /tmp/test-dir/subdir3
mkdir -p /tmp/extract-dir
touch /tmp/test-dir/subdir1/file1.txt
touch /tmp/test-dir/subdir1/file2.txt
touch /tmp/test-dir/subdir2/file3.txt
touch /tmp/test-dir/subdir2/file4.txt
touch /tmp/test-dir/subdir3/file5.txt
touch /tmp/test-dir/subdir3/file6.txt

Extracts assume the "/tmp/extract-dir" directory is empty.

tar

Create an archive.

# cd /tmp
# tar -cvf archive1.tar test-dir

Check the contents.

# tar -tvf /tmp/archive1.tar

Extract it.

# cd /tmp/extract-dir
# tar -xvf /tmp/archive1.tar

star

The star command may not be installed by default, but you can install it with the following command.

# yum install star

Create an archive.

# cd /tmp
# star -cv f=archive2.star test-dir

Check the contents.

# star -tv f=/tmp/archive2.star

Extract it.

# cd /tmp/extract-dir
# star -xv f=/tmp/archive2.star

gzip

The gzip command compresses the specified files, giving them a ".gz" extension. In this case we will use it to compress a ".tar" file.

# cd /tmp
# tar -cvf archive3.tar test-dir
# gzip archive3.tar

The "-z" option of the tar command allows you to do this directly.

# cd /tmp
# tar -cvzf archive3.tar.gz test-dir

The files are uncompressed using the gunzip command.

# gunzip archive3.tar.gz

The "-z" option of the tar command allows you to directly ungzip and extract a ".tar.gz" file.

# cd /tmp/extract-dir
# tar -xvzf /tmp/archive3.tar.gz

bzip2

The bzip2 command is similar to the gzip command. It compresses the specified files, giving them a ".bz2" extension. In this case we will use it to compress a ".tar" file.

# cd /tmp
# tar -cvf archive4.tar test-dir
# bzip2 archive4.tar

The "-j" option of the tar command allows you to do this directly.

# cd /tmp
# tar -cvjf archive4.tar.bz2 test-dir

The files are uncompressed using the bunzip2 command.

# bunzip2 archive4.tar.bz2

The "-j" option of the tar command allows you to directly bunzip2 and extract a ".tar.bz2" file.

# cd /tmp/extract-dir
# tar -xvjf /tmp/archive4.tar.bz2

zip

Create an archive.

# cd /tmp
# zip -r archive5.zip test-dir

Check the contents.

# unzip -l archive5.zip

Extract it.

# cd /tmp/extract-dir
# unzip /tmp/archive5.zip

cpio

Create an archive.

# cd /tmp
# find test-dir | cpio -ov > archive6.cpio

Check the contents.

# cpio -t < /tmp/archive6.cpio

Extract it.

# cd /tmp/extract-dir
# cpio -idmv < /tmp/archive6.cpio

Compress Files

See Linux Archive Tools (tar, star, gzip, bzip2, zip, cpio).
In order to save space on the filesystem you may wish to compress files such as archived redo logs. This can be using either the gzip or the compress commands. The gzip command results in a compressed copy of the original file with a ".gz" extension. The gunzip command reverses this process.

gzip myfile
gunzip myfile.gz

The compress command results in a compressed copy of the original file with a ".Z" extension. The uncompress command reverses this process.

compress myfile
uncompress myfile

Run Commands As Oracle User From Root

The following scripts shows how a number of commands can be run as the "oracle" user the "root" user.

#!/bin/ksh
su - oracle <<EOF
ORACLE_SID=LIN1; export ORACLE_SID
rman catalog=rman/rman@w2k1 target=/ cmdfile=my_cmdfile log=my_logfile append 
EOF

This is often necessary where CRON jobs are run from the root user rather than the oracle user.