Question

我希望能够在我拥有的某些.tex文件中出现的某些令牌出现之前添加换行符，其中一些令牌是'\ itemQ'，'\ pagebreakQ'。我创建了一个程序，最终创建了一个存储在$ sedInpt中的sed命令：

package apps.radwin.zxingprojectfragmenttwo;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link FragmentOne.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link FragmentOne#newInstance} factory method to
 * create an instance of this fragment.
 */
public class FragmentOne extends Fragment {
    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    private OnFragmentInteractionListener mListener;

    public FragmentOne() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment FragmentOne.
     */
    // TODO: Rename and change types and number of parameters
    public static FragmentOne newInstance(String param1, String param2) {
        FragmentOne fragment = new FragmentOne();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_fragment_one, container, false);
    }

    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p/>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

我想使用~$ echo "$sedInpt" -e s/$\\itemQ$/\n\1/ -e s/$\\pagebreakQ$/\n\1/作为sed的命令：

"$sedInpt"

但如果我做以下测试：

echo "$inputText" | eval "sed ${sedInpt}"

您可以看到在echo 'hello\itemQ' | eval "sed ${sedInpt}" hello\itemQ之前没有添加任何换行符。所以我尝试通过调用\itemQ来调试这种做事方式，以便详细了解发生了什么：

bash -x

您可以看到~$ bash -x ~$ echo "hello\itemQ" | eval "sed ${sedInpt}" + echo 'hello\itemQ' + eval 'sed -e s/$\\itemQ$/\n\1/ -e s/$\\pagebreakQ$/\n\1/' ++ sed -e 's/(\itemQ)/n1/' -e 's/(\pagebreakQ)/n1/' hello\itemQ和\n的反斜杠，甚至\1和(之前的反斜杠，我放在)似乎有"$sedInpt"解析时消失了。所以我有点迷失在接下来要做什么我想做什么......任何想法？

Answer 1

按照@Inian的建议，我设法通过这种方式实现了我想做的事情：

~$ sedInpt=( -e 's/\(\\itemQ\)/\n\1/' -e 's/\(\\pagebreakQ\)/\n\1/' )
~$ echo "hello\itemQ" | sed "${sedInpt[@]}"
hello
\itemQ

Answer 2

您也可以将它们组合成一个命令，我认为这更直接：

$ cat /tmp/sed.sh
sedInpt='s/\(\\itemQ\)/\n\1/; s/\(\\pagebreakQ\)/\n\1/'
echo "hello\itemQ" | sed "$sedInpt"
$ /tmp/sed.sh
hello
\itemQ

编辑：正如@ 123正确指出的那样，将命令存储在变量中是危险的，如果可能应该避免。如果您完全控制存储的内容，那么它应该是安全的，但如果它来自任何类型的用户输入，那么它就是一个命令注入＆＃34;漏洞。

错误，因为eval命令似乎删除了存储命令中的反斜杠

2 个答案: