When a "command not found" situation happens, Bash prints errors and ends with "Abort Trap: 6" instead of printing "Command not found"

[some1so]

For example, using 'derp' as a fake command (macports 5.2.15(1)-release):

~ $ derp
objc[75690]: +[__SwiftNativeNSStringBase initialize] may have been in progress in another thread when fork() was called.
objc[75690]: +[__SwiftNativeNSStringBase initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.
Abort trap: 6

expected behavior (Apple supplied 3.2.57):

~ $ derp
bash: derp: command not found
~ $