Should we reject commands with multiple inputs/outputs ?

[tao-guo]

The results are quite different between zsh and bash:

• multiple outputs

# zsh
➜ rust_cmd_lib git:(master) ✗ echo aaa >/tmp/f1 >/tmp/f2 >/tmp/f3
➜ rust_cmd_lib git:(master) ✗ cat /tmp/f1aaa
➜ rust_cmd_lib git:(master) ✗ cat /tmp/f2aaa
➜ rust_cmd_lib git:(master) ✗ cat /tmp/f3aaa
# bash
➜ rust_cmd_lib git:(master) ✗ bash~/src/rust/rust_cmd_lib$ echo aaa >/tmp/f4 >/tmp/f5 >/tmp/f6~/src/rust/rust_cmd_lib$ cat /tmp/f4~/src/rust/rust_cmd_lib$ cat /tmp/f5~/src/rust/rust_cmd_lib$ cat /tmp/f6aaa~/src/rust/rust_cmd_lib$

• multiple inputs

# zsh
➜ rust_cmd_lib git:(master) ✗ ls | wc -l < README.md281
# bash
➜ rust_cmd_lib git:(master) ✗ bash~/src/rust/rust_cmd_lib$ ls | wc -l < README.md 271

Since rust_cmd_lib can do parsing at compile time, we can actually reject such commands. Just want to know more feedback before making changes to reject such commands.