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wait [n ...]
Wait for each specified process and return its termination sta-
tus. Each n may be a process ID or a job specification; if a
job spec is given, all processes in that job's pipeline are
waited for. If n is not given, all currently active child pro-
cesses are waited for, and the return status is zero. If n
specifies a non-existent process or job, the return status is
127. Otherwise, the return status is the exit status of the
last process or job waited for.
したがって、次のように baackground プロセスが完了するのを待つことができます。
echo "oyoy 1" > file1 &
echo "yoyoyo 2" > file2 &
wait
rm -f file1 file2