The number of PIPEs (|) in one OS/2 command is limited to n, where n depends
on the length of the current value of the PATH variable. To get around
this limitation, group together parts of your command in parentheses.
Example: Instead of
a | b | c | d | e | f
use
(a | b | c) | (d | e | f)
(where a, b, c, d, e and f are OS/2 commands or programs). The parts in parentheses are executed by separate CMD processes and no CMD process must create more than 2 PIPEs.
Source: c't 1/1996