Tar: Difference between revisions
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By default, tar handles archiving symbolic links by writing a block to the archive with the name of the target of the link, thus preserving the symbolic link. However, if the [[#-h.7C--dereference|-h|--dereference]] option is used when creating the archive, tar archives the content of the file the symbolic link points to instead of the symbolic link information. | By default, tar handles archiving symbolic links by writing a block to the archive with the name of the target of the link, thus preserving the symbolic link. However, if the [[#-h.7C--dereference|-h|--dereference]] option is used when creating the archive, tar archives the content of the file the symbolic link points to instead of the symbolic link information. | ||
To create a portable archive aimed at systems that do not support symbolic links, use [[#-h.7C--dereference|-h|--dereference]]. | |||
=Handling Hard Links= | =Handling Hard Links= | ||
Revision as of 03:15, 25 December 2020
Internal
Handling Symbolic Links
By default, tar handles archiving symbolic links by writing a block to the archive with the name of the target of the link, thus preserving the symbolic link. However, if the -h|--dereference option is used when creating the archive, tar archives the content of the file the symbolic link points to instead of the symbolic link information.
To create a portable archive aimed at systems that do not support symbolic links, use -h|--dereference.
Handling Hard Links
Options
Archival
When tar is executed as root, the file permissions and owner are preserved.
-p
Preserve permissions, default when the root executes the command.
-s
Preserve order (same order). Sort names to extract to match archive.
-z
Compress, produce a tgz.archive.
-C
Source directory.
-h|--dereference
See Handling Symbolic Links above.
Archive
Archive maintaining the user IDs and file permissions:
tar -cvspf .../archive.tar *
Note that the name of the archive file to be created must immediately follow -f, without any interceding parameters.
To also gzip:
tar cfv - ./mydir | gzip > mydir.tgz
Exclude Specific Files from Archive
tar cf <file-name.tar> --exclude <pattern> <dir>
Do not process files or directories that match the specified pattern. Note that exclusions take precedence over patterns or filenames specified on the command line.
Example:
tar cfv module.tar --exclude */Jenkinsfile --exclude */jenkins module/
Restoration
Restore preserving the user ID and file permissions (if done as root, the behavior is implicit):
tar -xvspf .../archive.tar
Extract a Specified File
tar -xf archive.tar some/specific/file.txt gunzip < ... | tar xfv - some/specific/file.txt