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来源：雅诚德英语网
On a UNIX-based operating system, this is most easily accomplished by using the STDIN redirection character that is appropriate for your shell, such as the less-than symbol (<) for the Bash shell.
在基于UNIX 的操作系统中，通过使用适合您的shell的STDIN重定向字符最容易实现了，比如为 Bash shell 使用小于号 (<)。