You will notice that on a US keyboard, shift-4 is "$", which is the bash variable expansion character.

注意到了吗：在美国键盘上，shift-4 是 "$"，它是 bash 变量扩展字符。

youdao

Using AB-8 resin as solid phase, the expansion character and liquid mixing performance in the expanded bed were studied.

以AB - 8大孔树脂为固相，对膨胀床的膨胀特性及流体混合性能进行了研究。

youdao

For example, the "! "character is the history expansion character, which bash normally replaces with a previously-typed command.

例如，“ ！ ”字符是历史扩展字符，bash通常将其替换为前面输入的命令。

youdao

Harmondsworth Village in west London was designated a conservation area in 1970 but the open countryside famed for being a medieval settlement could lose its character because of the expansion of Heathrow Airport, according to English Heritage.

BBC: London's unique areas 'at risk'

An expansion pack is sorely needed at this point, however, and preferably one with a couple new playable character types and a bunch of new areas.

FORBES: Connect