tar: Reading
1
1 4.4.1 Options to Help Read Archives
1 -----------------------------------
1
1 Normally, 'tar' will request data in full record increments from an
1 archive storage device. If the device cannot return a full record,
1 'tar' will report an error. However, some devices do not always return
1 full records, or do not require the last record of an archive to be
1 padded out to the next record boundary. To keep reading until you
1 obtain a full record, or to accept an incomplete record if it contains
1 an end-of-archive marker, specify the '--read-full-records' ('-B')
1 option in conjunction with the '--extract' or '--list' operations.
1 ⇒Blocking.
1
1 The '--read-full-records' ('-B') option is turned on by default when
1 'tar' reads an archive from standard input, or from a remote machine.
1 This is because on BSD Unix systems, attempting to read a pipe returns
1 however much happens to be in the pipe, even if it is less than was
1 requested. If this option were not enabled, 'tar' would fail as soon as
1 it read an incomplete record from the pipe.
1
1 If you're not sure of the blocking factor of an archive, you can read
1 the archive by specifying '--read-full-records' ('-B') and
1 '--blocking-factor=512-SIZE' ('-b 512-SIZE'), using a blocking factor
1 larger than what the archive uses. This lets you avoid having to
1 determine the blocking factor of an archive. ⇒Blocking Factor.
1
Menu