unbuffer(1) ignores errors from programs that were killed by a signal:
$ perl -e 'use POSIX; raise(SIGABRT)'
Aborted
$ echo $?
134
$ unbuffer perl -e 'use POSIX; raise(SIGABRT)'
$ echo $?
0
unbuffer(1) ignores errors from programs that were killed by a signal:
$ perl -e 'use POSIX; raise(SIGABRT)'
Aborted
$ echo $?
134
$ unbuffer perl -e 'use POSIX; raise(SIGABRT)'
$ echo $?
0