Delimiter not working for special characters in COPY command from CQLSH

COPY command from CQLSH which can be used to load data from CSV files is not working with option delimiter='\t'

cqlsh>CREATE TABLE airplanes (
name text PRIMARY KEY,
manufacturer ascii,
year int,
mach float
);

cqlsh>INSERT INTO airplanes (name, manufacturer, year, mach) VALUES ('P38-Lightning', 'Lockheed', 1937, 7);

cqlsh> SELECT * FROM airplanes;
name | mach | manufacturer | year
-----------------------------+-----
P38-Lightning | 0.7 | Lockheed | 1937

cqlsh> COPY airplanes (name, manufacturer, year, mach) TO 'temp.tsv' WITH DELIMITER = '\t';
"delimiter" must be an 1-character string

cqlsh> COPY airplanes (name, manufacturer, year, mach) FROM 'temp.csv' WITH DELIMITER = '\t';
"delimiter" must be an 1-character string