[LPIC-1]Scripting and Data Management 13

When the command echo $$ outputs 12942, what is the meaning of 12942?

A. It is the process ID of the echo command.
B. It is the process ID of the current shell.
C. It is the process ID of the last command executed.
D. It is the process ID of the last command which has been placed in the background.

題解

「$$」會儲存目前shell的行程(process)ID,所以答案是選項B。

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