tar: gnu

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1 8.3.6 GNU and old GNU 'tar' format
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1 GNU 'tar' was based on an early draft of the POSIX 1003.1 'ustar'
1 standard.  GNU extensions to 'tar', such as the support for file names
1 longer than 100 characters, use portions of the 'tar' header record
1 which were specified in that POSIX draft as unused.  Subsequent changes
1 in POSIX have allocated the same parts of the header record for other
1 purposes.  As a result, GNU 'tar' format is incompatible with the
1 current POSIX specification, and with 'tar' programs that follow it.
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1    In the majority of cases, 'tar' will be configured to create this
1 format by default.  This will change in future releases, since we plan
1 to make 'POSIX' format the default.
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1    To force creation a GNU 'tar' archive, use option '--format=gnu'.
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