Linux/Unix tar Command with Practical Examples

 Options:

•      -d, –diff, –compare —> find differences between archive and file system
•      -r, –append —> append files to the end of an archive
•      -A, –catenate, –concatenate  —-> append tar files to an archive
•      -t, –list    —-> list the contents of an archive
•      –test-label —> test the archive volume label and exit
•      -u, –update —> only append files newer than copy in archive
•      –delete —> delete from the archive (not on mag tapes!)
•      -x, –extract, –get    —-> extract files from an archive     
•      -c, –create —-> create a new archive

Example:1 Create an Archive File

Syntax : # tar cvf <archive-Name>.tar /<file-OR-Directories To Be archived>

# tar cvf /mnt/backup.tar /etc /usr

Above command will archive all the files and directories of /etc and /usr in backup.tar file.

Example:2 Extract the data from the archive file.

# tar xpvf backup.tar -C /mnt/

Above Command will extract files or directories in /mnt folder.

Example:3 List archive file contents without extracting

# tar tvf /mnt/backup.tar

Example:4 Create archive using gzip compression technique.

# tar zcpvf /mnt/backup-$(date +%d-%m-%Y).tar.gz /etc /usr

OR

# tar zcpvf /mnt/backup-$(date +%d-%m-%Y).tgz /etc /usr

Above Command will take the backup or archive of /etc & /usr folder according the current date & also compress the tar file using gzip.

Example:5 Create archive using bzip compression technique.

# tar jcpvf /mnt/backup-$(date +%d-%m-%Y).tar.bz2 /etc /usr

OR

# tar jcpvf /mnt/backup-$(date +%d-%m-%Y).tbz /etc /usr

Above Command will take the backup or archive of /etc & /usr folder according the current date & also compress the tar file using bzip.

Example:6 Extract data from .tar.gz or .tgz and .tar.bz2 or .tbz

# tar zxpvf /mnt/backup-21-03-2013.tgz -C /location-where-to-extract
# tar jxpvf /mnt/backup-21-03-2013.tbz -C /location-where-to-extract

Example:7 Extract Particular file and directory from the archive (.tar.gz or .tgz and .tar.bz2 or .tbz)

# tar jxpvf backup-21-03-2013.tbz etc/passwd

Above Command will extract passwd file from the backup tar file in the current directory.

# tar jxpvf backup-21-03-2013.tbz etc/apache2

Above command will extract the directory apache2 in the current directory

Example:8 Append new file or directory to the existing archive file using -r option

We cannot add file or directory to a compressed archive , so first we have to uncompress it , so that it has an extension of “.tar”

# tar rvf /mnt/backup-21-03-2013.tar vmlinuz-3.2.0-38-generic

Above command will append the vmlinuz file to backup tar file , to append directory to an archive replace the file with directory name in the above command.

Example:9 Excluding files & Directories while taking backup using tar

There are some scenarios where we have to take the backup of a directory and have to exclude particular file in that directory.

Example : Take the backup of /etc directory & exclude a subdirectory directory (/etc/sysconfig/network-scripts).

# tar -zcpvf etc-$(date +%d-%m-%Y).tgz --exclude /etc/sysconfig/network-scripts/ /etc/

Excluding files and directories using a file , this can be done via (–exclude-from or short form -X ).Create a file exclude.txt under /root folder, should have content: “/etc/sysconfig/network-scripts”

# tar -zcpvf etc-$(date +%d-%m-%Y).tgz -X /root/exclude.txt /etc/

Above command will take the backup of /etc folder excluding subdirectory“/etc/sysconfig/network-scripts”

Example:10 Backup using -T & -X option in tar

Where:

-T : get names to extract or create from FILE
-X : exclude patterns listed in FILE

In Some scenario , where we want to specify the files to be backed up and some files to be excluded from the backup.

Create file /root/include.txt ,
/etc
/home

Create a file /root/exclude.txt
/etc/sysconfig/network-scripts
/etc/fstab

Now Take the backup using below command

# tar -zcpvf backup-$(date +%d-%m-%Y).tgz -T /root/include.txt -X /root/exclude.txt

Above command will take the backup of all files and directories mentioned in include.txt and will exculde files & directories mentioned in the exclude.txt file.