$ export A=5
$ ./bin/env ./bin/repeat 1 A
A=5
$ ./bin/env B=6 C=7 ./bin/repeat 1 A 2 B 3 C
A=5
B=6
B=6
C=7
C=7
C=7
$ ./bin/env C=7 ./bin/repeat 1 A 2 B 3 C | head -n 4
A=5
B=
B=
C=7
$ quit