为什么我可以回显环境变量但不能将它用于cd或ls？

Question

为什么我可以echo $RUBYPATH变量：

[grant@rails-box app]$ echo $RUBYPATH
/opt/rubies/ruby-2.3.0

ls该目录：

[grant@rails-box app]$ ls /opt/rubies/ruby-2.3.0
bin  include  lib  share

但我不能ls使用变量？

[grant@rails-box app]$ ls $RUBYPATH
: No such file or directoryes/ruby-2.3.0

Answer 1

Bishop是对的：尝试

$ echo $RUBYPATH | cat -v # or hexdump -C