tar: interactive

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1 3.10 Asking for Confirmation During Operations
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1 Typically, 'tar' carries out a command without stopping for further
1 instructions.  In some situations however, you may want to exclude some
1 files and archive members from the operation (for instance if disk or
1 storage space is tight).  You can do this by excluding certain files
1 automatically (⇒Choosing), or by performing an operation
1 interactively, using the '--interactive' ('-w') option.  'tar' also
1 accepts '--confirmation' for this option.
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1    When the '--interactive' ('-w') option is specified, before reading,
1 writing, or deleting files, 'tar' first prints a message for each such
1 file, telling what operation it intends to take, then asks for
1 confirmation on the terminal.  The actions which require confirmation
1 include adding a file to the archive, extracting a file from the
1 archive, deleting a file from the archive, and deleting a file from
1 disk.  To confirm the action, you must type a line of input beginning
1 with 'y'.  If your input line begins with anything other than 'y', 'tar'
1 skips that file.
1 
1    If 'tar' is reading the archive from the standard input, 'tar' opens
1 the file '/dev/tty' to support the interactive communications.
1 
1    Verbose output is normally sent to standard output, separate from
1 other error messages.  However, if the archive is produced directly on
1 standard output, then verbose output is mixed with errors on 'stderr'.
1 Producing the archive on standard output may be used as a way to avoid
1 using disk space, when the archive is soon to be consumed by another
1 process reading it, say.  Some people felt the need of producing an
1 archive on stdout, still willing to segregate between verbose output and
1 error output.  A possible approach would be using a named pipe to
1 receive the archive, and having the consumer process to read from that
1 named pipe.  This has the advantage of letting standard output free to
1 receive verbose output, all separate from errors.
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