Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions
Privacy Policy

  




 

 

Writing to an External Program

You can instruct tar to send the contents of each extracted file to the standard input of an external program:

--to-program=command
Extract files and pipe their contents to the standard input of command. When this option is used, instead of creating the files specified, tar invokes command and pipes the contents of the files to its standard output. Command may contain command line arguments. The program is executed via sh -c. Notice, that command is executed once for each regular file extracted. Non-regular files (directories, etc.) are ignored when this option is used.

The command can obtain the information about the file it processes from the following environment variables:

TAR_FILETYPE
Type of the file. It is a single letter with the following meaning:

f Regular file
d Directory
l Symbolic link
h Hard link
b Block device
c Character device

Currently only regular files are supported.


TAR_MODE
File mode, an octal number.


TAR_FILENAME
The name of the file.


TAR_REALNAME
Name of the file as stored in the archive.


TAR_UNAME
Name of the file owner.


TAR_GNAME
Name of the file owner group.


TAR_ATIME
Time of last access. It is a decimal number, representing seconds since the epoch. If the archive provides times with nanosecond precision, the nanoseconds are appended to the timestamp after a decimal point.


TAR_MTIME
Time of last modification.


TAR_CTIME
Time of last status change.


TAR_SIZE
Size of the file.


TAR_UID
UID of the file owner.


TAR_GID
GID of the file owner.

In addition to these variables, TAR_VERSION contains the GNU tar version number.

If command exits with a non-0 status, tar will print an error message similar to the following:

     tar: 2345: Child returned status 1

Here, ‘2345’ is the PID of the finished process.

If this behavior is not wanted, use --ignore-command-error:

--ignore-command-error
Ignore exit codes of subprocesses. Notice that if the program exits on signal or otherwise terminates abnormally, the error message will be printed even if this option is used.


--no-ignore-command-error
Cancel the effect of any previous --ignore-command-error option. This option is useful if you have set --ignore-command-error in TAR_OPTIONS (see TAR_OPTIONS) and wish to temporarily cancel it.

 
 
  Published under the terms of the GNU General Public License Design by Interspire