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 Append summary info from the current run to a HISTORY file in the day directory 
 Script should be run from the directory immediately above the day directory
 Assumes that the p and q files are not compressed
  
 Usage: sh_history -dir <daydir> [-erase] 
  
    Required:  <daydir> name of day directory to be accessed
    
    -erase is usually omitted; if included then erase and begin a new HISTORY file
 
 Example:  sh_history -dir 205r 
  
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