The following [[script?]] demonstrates how the substr function and length functions can be combined to remove the first and last [[character?]]s from a string:
BEGIN {
mystring="knights"
print substr(mystring,2) # remove the first letter
print substr(mystring,1,length(mystring)-1) # remove the last character
print substr(mystring,2,length(mystring)-2) # remove both the first and last character
}