Interactive Find and Replace String Patterns on Multiple Files

Discussion in 'Java' started by Xah Lee, Jun 14, 2006.

  1. Xah Lee

    Xah Lee Guest

    Interactive Find and Replace String Patterns on Multiple Files

    Xah Lee, 2006-06

    Suppose you need to do find and replace of a string pattern, for all
    files in a directory. However, you do not want to replace all of them.
    You need to look at it in a case-by-case basis. What can you do?

    Answer: emacs.

    Here's how you do it.
    Select Target Files

    Start emacs by typing “emacs†in the command line interfaceprompt.

    Now you need to locate the directory and files you want to
    find/replace. Type “esc x find-diredâ€. (then press Enter) Then,
    give a directory name, e.g. “/Users/mary/myfilesâ€

    Emacs will ask you with the prompt “Run find (with args): â€.. If you
    need to do the replacement on all html files, then give “-name
    "*html"â€. If you don't care about what kind of file but simply all
    files under that dir, then give “-type fâ€.

    Now, you will be shown the list of files, and now you need to
    “mark†the files you want the regex find-replace to work on.. You
    mark a file by moving the cursor to the file you want, then press m.
    Unmark it by pressing u. To mark all files by a regex, type “% mâ€,
    then give your pattern. Suppose you want to mark all html files, then
    type “% m html$â€.
    Interactive Find & Replace

    Now, you are ready to do the interactive find replace. For simplicity,
    let's say you just want to replace the word “quick†by “superâ€
    depending on the context. Now, type “esc x
    dired-do-query-replace-regexpâ€. It will prompt you for the regex
    string and the replacement string. Type “quick†then “superâ€.

    Now, emacs will use your pattern and check the files, and stop and show
    you whenever a match occurred. When this happens, emacs will prompt
    you, and you have a choice of making the change or skip the change. To
    make the change, type y. To skip, type n. If you simply want emacs to
    go ahead and make all such changes to the current files, type “!â€.
    If you want to cancel the whole operation, type control-g.
    Saving the Changed Files

    Now, after you went through the above ordeal. There is one more step
    you need to do, and that is saving the changed files. This you can do,
    by typing “esc x list-bufferâ€, then move the cursor to the file you
    want to save and press s. It will mark the file for later save action.
    Type u to unmark. Once you are done, type x to execute the saving of
    all S marked files. (in emacs, opened file is called “bufferâ€.
    Disregard ohter things there.)

    Alternatively, you can also type “esc x save-some-buffersâ€.Then
    emacs will show each buffer for you and ask if you want it saved.

    If you have emacs version 22, you can use “M-x ibuffer†to mark all
    files you want to save by a regex.


    PS if anyone know any tool or perl/python/lisp program that can also do
    this, i'd be interested to know. Thanks.

    This post is archived at:


    Xah Lee, Jun 14, 2006
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