One critical variable is the value of PATH, which you can check at the command line with the echo $PATH command.

一个临界变数是路径的数值， 你以回声$路径指令能在指令行检查。

youdao

If you're appending only a single line instead of multiple lines or an entire file, you can use echo instead of cat.

如果您仅追加单行而不是多行或整个文件，您可以使用echo而不是cat。

youdao

Did you also notice the use of double-quoted strings instead of single-quoted strings on the echo line?

另外，你注意到在echo一行它使用了双引号而不是单引号吗？

youdao

This is the story of Echo Taps: The Long Brass Line.

FORBES: 42 Miles Of Echo Taps: A Memorial Day Tribute