This variable set the approximate maximum size, in
bytes, of a file to be mailed to the user. Any output
larger than this limit will be split in pieces of about
this size.  This can be set by the user in the range 1024
to ~2Gb with a default of 51200 bytes. Some mail
gateways will not allow results of over 100Kb and so
care should be taken when setting this limit.
