On some (but not all) operating systems assigning to $0 modifies the argument area that the ps program sees. On some platforms you may have to use special ps options or a different ps to see the changes. Modifying the $0 is more useful as a way of indicating the current program state than it is for hiding the program you're running. 一部の(しかし全てではありません)オペレーティングシステムでは $0 に代入を行なうことで ps プログラムが見る引数エリアを修正