17.6.1.0245
/STRING
slash-string
STRING
 
( c-addr1 u1 n -- c-addr2 u2 )

Adjust the character string at c-addr1 by n characters. The resulting character string, specified by c-addr2 u2, begins at c-addr1 plus n characters and is u1 minus n characters long.

See:
A.17.6.1.0245 /STRING.

Rationale:
/STRING is used to remove or add characters relative to the current position in the character string. Positive values of n will exclude characters from the string while negative values of n will include characters to the left of the string.

S" ABC" 2 /STRING 2DUP TYPE \ outputs "C"
-1 /STRING TYPE \ outputs "BC"

Testing:
T{ s1  5 /STRING -> s1 SWAP 5 + SWAP 5 - }T
T{ s1 10 /STRING -4 /STRING -> s1 6 /STRING }T
T{ s1  0 /STRING -> s1 }T