fish shell 如何获取后台启动进程的PID

Question

在 FiSH（友好互动 SHell）中，我可以在后台启动一个进程 (something &)。但是，如果我尝试检索进程的进程 ID (PID=$!)，我会从 fish:

中收到错误消息

fish: Unknown command “PID=$!”. Did you mean “set PID $!”? For information on assigning values to variables, see the
help section on the set command by typing “help set”.
PID=$!: command not found

如何获取后台进程的PID？

Answer 1

使用process expansion，你可以写

set PID %1          # if you know it's the first background job
set PID %something  # if you know it's the only "something" running

请注意，此功能是 removed in fish version 3。

否则，我们可以使用jobs命令

set PID (jobs -l | awk '{print }')    # just get the pid
jobs -l | read jobid pid cpu state cmd  # get all the things

Answer 2

从 fish version 3 开始，您可以使用 $last_pid 代替 %last 来获取最后一个后台作业的 PID。

fish shell 如何获取后台启动进程的PID

Fish shell how to get the PID of the process started in the background

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