3.3.13 Changing Record Size
The "augment" option makes it possible to increase the maximum record size of
a Vision file. This is useful for adding fields to a record without having to
rebuild the entire data file. The new maximum record size and the file name is
specified after this option as shown in the examples below:
vutil -augment [ -q ] <new_max_rec_size> [filename]
vutil -augment [ -q ] 50 myfile.dat
cat vision_filelist | vutil -augment [ -q ] 100
Note that if the Vision file originally had a fixed-length record size, and if the
new maximum record size is larger than the old maximum record size, the file
effectively has a variable-length record size after running this command.
You may specify a new maximum record size that is smaller than the current
maximum record size, but not smaller than the current minimum record size. This
enables you to correct for the case that the maximum was raised too high by
mistake. Be warned, though, that if any records were added while the maximum was
at its higher level, the file is marked as broken when those records are next
read, because Vision detects that a record exists that is larger than the current
(reduced) maximum record size. Vutil issues a warning cautioning that you are
reducing the maximum record size below the current value.
Since this operation changes the logical structure of the file, exclusive file
access is required. Vutil reports "File locked" if any other process has the
file open.
The "-q" option causes vutil to exit (with status 99) if user interaction is required.