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(tar.info)interactive

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Asking for Confirmation During Operations
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   Typically, `tar' carries out a command without stopping for further
instructions.  In some situations however, you may want to exclude some
files and archive members from the operation (for instance if disk or
storage space is tight).  You can do this by excluding certain files
automatically (Note: Choosing), or by performing an operation
interactively, using the `--interactive' (`-w') option.  `tar' also
accepts `--confirmation' for this option.

   When the `--interactive' (`-w') option is specified, before reading,
writing, or deleting files, `tar' first prints a message for each such
file, telling what operation it intends to take, then asks for
confirmation on the terminal.  The actions which require confirmation
include adding a file to the archive, extracting a file from the
archive, deleting a file from the archive, and deleting a file from
disk.  To confirm the action, you must type a line of input beginning
with `y'.  If your input line begins with anything other than `y',
`tar' skips that file.

   If `tar' is reading the archive from the standard input, `tar' opens
the file `/dev/tty' to support the interactive communications.

   Verbose output is normally sent to standard output, separate from
other error messages.  However, if the archive is produced directly on
standard output, then verbose output is mixed with errors on `stderr'.
Producing the archive on standard output may be used as a way to avoid
using disk space, when the archive is soon to be consumed by another
process reading it, say.  Some people felt the need of producing an
archive on stdout, still willing to segregate between verbose output
and error output.  A possible approach would be using a named pipe to
receive the archive, and having the consumer process to read from that
named pipe.  This has the advantage of letting standard output free to
receive verbose output, all separate from errors.