=chgkkkwval = 
{{{
Usage: chgkwval <keywordlist_file> <keyword> <value>
Changes the keyword value within the keyword list to value specified.
Example:   chgval band1.spec area.size "pixels 7689 8031"
Changes the keyword value of area.size to pixels 7689 8031

Note 1:  Use no colon ":" after the keyword.
Note 2:  If the keyword is present in the keyword list it will
         be overwritten.
Note 3:  If the keyword is not in the keyword list it will be added.
Note 4:  Enclose value in double quotes if it is more than one string.
}}}