LOG-COPY:  Copy part of a log file to a new log file.

Log-copy copies certain records from an existing log file to a new log
file.  This is useful for decimating log files or repairing log files
with junk at the end, such as could arise if a program crashes in the
middle of writing a record.

Usage:

   log-copy [ -ignoredtype... ] logfile-in range logfile-out [ low[%mod] ]

Records with negative indexes or with indexes in the indicated range
are copied from logfile-in to a newly-created logfile-out, except that
records with the types given in the optional first argument are
ignored.  (See log-types.doc for a listing of conventionally-used
record types.).  The range has the usual [low][:[high]][%modulus]
form, as described in parse_range in misc.c.  If high and the colon
are omitted, high defaults to low.  If high is omitted but the colon
is present, the range extends to the end of the file.

If the optional trailing argument is present, the indexes of the
records written (other than those with negative indexes) are changed
so that the first record has index 'low' and subsequent indexes
increase by 'mod'.  The default for 'mod' is the modulus in the input
range.

As a special fudge, an input file range of "-" causes only records
with negative indexes to be copied.

            Copyright (c) 1995-2003 by Radford M. Neal