是的，你可以（我没有测试过下面的代码）：

# ensure #section A exists in the file:
if ! grep -q '^#section A' kafka.configuration; then
  echo '#section A' >> kafka.configuration
fi

# then append to it (next line) your config line:
num_cpu=32
if grep -q '^num.replica.fetchers' kafka.configuration; then
  sed -i "/num.replica.fetchers/s/=.*$/= $num_cpu/g" kafka.configuration
else
  sed -i "/#section A/a num.replica.fetchers = $num_cpu" kafka.configuration
fi

您还可以使用grep来检查#section A之后是否有匹配项（在接下来的几行中）