In most cases, this was already necessary to prevent their misinterpretation by the shell. This behaviour is now prohibited due to concerns about introducing susceptibility to trojan horses, which the user might be trying to avoid by leaving dot out of PATH . It is unlikely that any application ever relied on it not being passed. In applications, the reserved exit status values 126 and 127 should be avoided, except as described in the XCU specifiation. Values greater than 128 should be reserved for signal terminations.
Scripts relying on a specific system's trap output format have to be recoded.
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