cpytap manipulates a .tap magtape container file used by SIMH. It copies an
existing .tap file to a newly created .tap while modifying its file level
contents. While performing the copy, individual files may be skipped or
replaced and new files may be inserted at specified positions or appended
after the last source file has been copied. For files which are copied between
the source and destination tapes, the internal record structure of each file
is maintained. Replacement or inserted/appended files may only be written
with a specified maximum record size.

cpytap is invoked by:

        cpytap src dst [-r len] [-I n,file] [-R n,file] [-S n] [-A file]

Where:

        -r len    Max record size to be used when writing new files to the
                  destination tape. (1 <= len <= 65536, default 10240).
                  There may be multiple "-r" switches on the command line.
                  When a "-r" switch is specified, it takes effect on all
                  following editing commands.

        -I n,file Insert the specified file before file n of the source tape

        -R n,file Replace file n of the source tape with the specified file

        -S n      Skip file n of the source tape

        -A file   Append the specified fie after all the files on the source
                  tape have been copied to the destination tape.

Files on the source tape are numbered 1 - n.

When multiple -I commands reference the same source tape file or there are
multiple -A commands, the files will be written to the destination tape in
the order specified on the command line. If a -R command and a -I command
reference the same source tape file, the -R file will be written first
followed by the -I file(s).

The editing control tables are pre-built into the executable. Edit commands
may be issued for files 1 - 100, subsequent files will just be copied from
source to destination. There may be up to 20 -I commands for each source tape
file and up to 20 -A commands.