fish shell 如何在后台启动进程的PID

Question

在FiSH(友好交互式 shell )中，我可以在后台启动一个进程(something &)。但是，如果尝试检索该进程的进程ID(PID=$!)，则会从fish中得到一个错误:

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，您可以编写

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 $2}')    # just get the pid
jobs -l | read jobid pid cpu state cmd  # get all the things