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Diffstat (limited to 'runtime/doc/undo.txt')
| -rw-r--r-- | runtime/doc/undo.txt | 90 |
1 files changed, 87 insertions, 3 deletions
diff --git a/runtime/doc/undo.txt b/runtime/doc/undo.txt index 2c8c60c9a..05e5555b7 100644 --- a/runtime/doc/undo.txt +++ b/runtime/doc/undo.txt @@ -12,7 +12,8 @@ The basics are explained in section |02.5| of the user manual. 2. Two ways of undo |undo-two-ways| 3. Undo blocks |undo-blocks| 4. Undo branches |undo-branches| -5. Remarks about undo |undo-remarks| +5. Undo persistence |undo-persistence| +6. Remarks about undo |undo-remarks| ============================================================================== 1. Undo and redo commands *undo-commands* @@ -22,7 +23,7 @@ u Undo [count] changes. {Vi: only one level} *:u* *:un* *:undo* :u[ndo] Undo one change. {Vi: only one level} - + *E830* :u[ndo] {N} Jump to after change number {N}. See |undo-branches| for the meaning of {N}. {not in Vi} @@ -109,6 +110,8 @@ change. To do the opposite, break a change into two undo blocks, in Insert mode use CTRL-G u. This is useful if you want an insert command to be undoable in parts. E.g., for each sentence. |i_CTRL-G_u| +Setting the value of 'undolevels' also breaks undo. Even when the new value +is equal to the old value. ============================================================================== 4. Undo branches *undo-branches* *undo-tree* @@ -201,7 +204,88 @@ Note that using "u" and CTRL-R will not get you to all possible text states while repeating "g-" and "g+" does. ============================================================================== -5. Remarks about undo *undo-remarks* +5. Undo persistence *undo-persistence* *persistent-undo* + +When unloading a buffer Vim normally destroys the tree of undos created for +that buffer. By setting the 'undofile' option, Vim will automatically save +your undo history when you write a file and restore undo history when you edit +the file again. + +The 'undofile' option is checked after writing a file, before the BufWritePost +autocommands. If you want to control what files to write undo information +for, you can use a BufWritePre autocommand: > + au BufWritePre /tmp/* setlocal noundofile + +Vim saves undo trees in a separate undo file, one for each edited file, using +a simple scheme that maps filesystem paths directly to undo files. Vim will +detect if an undo file is no longer synchronized with the file it was written +for (with a hash of the file contents) and ignore it when the file was changed +after the undo file was written, to prevent corruption. + +Undo files are normally saved in the same directory as the file. This can be +changed with the 'undodir' option. + +You can also save and restore undo histories by using ":wundo" and ":rundo" +respectively: + *:wundo* *:rundo* +:wundo[!] {file} + Write undo history to {file}. + When {file} exists and it does not look like an undo file + (the magic number at the start of the file is wrong), then + this fails, unless the ! was added. + If it exists and does look like an undo file it is + overwritten. + {not in Vi} + +:rundo {file} Read undo history from {file}. + {not in Vi} + +You can use these in autocommands to explicitly specify the name of the +history file. E.g.: > + + au BufReadPost * rundo %:h/UNDO/%:t + au BufWritePost * wundo %:h/UNDO/%:t + +You should keep 'undofile' off, otherwise you end up with two undo files for +every write. +Note: I did not verify this always works! + +Note that while reading/writing files and 'undofile' is set most errors will +be silent, unless 'verbose' is set. With :wundo and :rundo you will get more +error messages, e.g., when the file cannot be read or written. + +NOTE: undo files are never deleted by Vim. You need to delete them yourself. + +Reading an existing undo file may fail for several reasons: +*E822* It cannot be opened, because the file permissions don't allow it. +*E823* The magic number at the start of the file doesn't match. This usually + means it is not an undo file. +*E824* The version number of the undo file indicates that it's written by a + newer version of Vim. You need that newer version to open it. Don't + write the buffer if you want to keep the undo info in the file. +"Undo file contents changed" + The file text differs from when the undo file was written. This means + the undo file cannot be used, it would corrupt the text. +*E825* *E826* The undo file does not contain valid contents and cannot be + used. +*E827* The magic number at the end of the file was not found. This usually + means the file was truncated. + +Writing an undo file may fail for these reasons: +*E828* The file to be written cannot be created. Perhaps you do not have + write permissions in the directory. +"Will not overwrite with undo file, cannot read" + A file exists with the name of the undo file to be written, but it + cannot be read. You may want to delete this file or rename it. +"Will not overwrite, this is not an undo file" + A file exists with the name of the undo file to be written, but it + does not start with the right magic number. You may want to delete + this file or rename it. +*E829* An error occurred while writing the undo file. You may want to try + again. + +============================================================================== +6. Remarks about undo *undo-remarks* The number of changes that are remembered is set with the 'undolevels' option. If it is zero, the Vi-compatible way is always used. If it is negative no |