1*recover.txt* For Vim version 7.3. Last change: 2010 Jul 20 2 3 4 VIM REFERENCE MANUAL by Bram Moolenaar 5 6 7Recovery after a crash *crash-recovery* 8 9You have spent several hours typing in that text that has to be finished 10next morning, and then disaster strikes: Your computer crashes. 11 12 DON'T PANIC! 13 14You can recover most of your changes from the files that Vim uses to store 15the contents of the file. Mostly you can recover your work with one command: 16 vim -r filename 17 181. The swap file |swap-file| 192. Recovery |recovery| 20 21============================================================================== 221. The swap file *swap-file* 23 24Vim stores the things you changed in a swap file. Using the original file 25you started from plus the swap file you can mostly recover your work. 26 27You can see the name of the current swap file being used with the command: 28 29 :sw[apname] *:sw* *:swapname* 30 31The name of the swap file is normally the same as the file you are editing, 32with the extension ".swp". 33- On Unix, a '.' is prepended to swap file names in the same directory as the 34 edited file. This avoids that the swap file shows up in a directory 35 listing. 36- On MS-DOS machines and when the 'shortname' option is on, any '.' in the 37 original file name is replaced with '_'. 38- If this file already exists (e.g., when you are recovering from a crash) a 39 warning is given and another extension is used, ".swo", ".swn", etc. 40- An existing file will never be overwritten. 41- The swap file is deleted as soon as Vim stops editing the file. 42 43Technical: The replacement of '.' with '_' is done to avoid problems with 44 MS-DOS compatible filesystems (e.g., crossdos, multidos). If Vim 45 is able to detect that the file is on an MS-DOS-like filesystem, a 46 flag is set that has the same effect as the 'shortname' option. 47 This flag is reset when you start editing another file. 48 *E326* 49 If the ".swp" file name already exists, the last character is 50 decremented until there is no file with that name or ".saa" is 51 reached. In the last case, no swap file is created. 52 53By setting the 'directory' option you can place the swap file in another place 54than where the edited file is. 55Advantages: 56- You will not pollute the directories with ".swp" files. 57- When the 'directory' is on another partition, reduce the risk of damaging 58 the file system where the file is (in a crash). 59Disadvantages: 60- You can get name collisions from files with the same name but in different 61 directories (although Vim tries to avoid that by comparing the path name). 62 This will result in bogus ATTENTION warning messages. 63- When you use your home directory, and somebody else tries to edit the same 64 file, he will not see your swap file and will not get the ATTENTION warning 65 message. 66On the Amiga you can also use a recoverable ram disk, but there is no 100% 67guarantee that this works. Putting swap files in a normal ram disk (like RAM: 68on the Amiga) or in a place that is cleared when rebooting (like /tmp on Unix) 69makes no sense, you will lose the swap file in a crash. 70 71If you want to put swap files in a fixed place, put a command resembling the 72following ones in your .vimrc: 73 :set dir=dh2:tmp (for Amiga) 74 :set dir=~/tmp (for Unix) 75 :set dir=c:\\tmp (for MS-DOS and Win32) 76This is also very handy when editing files on floppy. Of course you will have 77to create that "tmp" directory for this to work! 78 79For read-only files, a swap file is not used. Unless the file is big, causing 80the amount of memory used to be higher than given with 'maxmem' or 81'maxmemtot'. And when making a change to a read-only file, the swap file is 82created anyway. 83 84The 'swapfile' option can be reset to avoid creating a swapfile. 85 86 87Detecting an existing swap file ~ 88 89You can find this in the user manual, section |11.3|. 90 91 92Updating the swapfile ~ 93 94The swap file is updated after typing 200 characters or when you have not 95typed anything for four seconds. This only happens if the buffer was 96changed, not when you only moved around. The reason why it is not kept up to 97date all the time is that this would slow down normal work too much. You can 98change the 200 character count with the 'updatecount' option. You can set 99the time with the 'updatetime' option. The time is given in milliseconds. 100After writing to the swap file Vim syncs the file to disk. This takes some 101time, especially on busy Unix systems. If you don't want this you can set the 102'swapsync' option to an empty string. The risk of losing work becomes bigger 103though. On some non-Unix systems (MS-DOS, Amiga) the swap file won't be 104written at all. 105 106If the writing to the swap file is not wanted, it can be switched off by 107setting the 'updatecount' option to 0. The same is done when starting Vim 108with the "-n" option. Writing can be switched back on by setting the 109'updatecount' option to non-zero. Swap files will be created for all buffers 110when doing this. But when setting 'updatecount' to zero, the existing swap 111files will not be removed, it will only affect files that will be opened 112after this. 113 114If you want to make sure that your changes are in the swap file use this 115command: 116 117 *:pre* *:preserve* *E313* *E314* 118:pre[serve] Write all text for all buffers into swap file. The 119 original file is no longer needed for recovery. 120 This sets a flag in the current buffer. When the '&' 121 flag is present in 'cpoptions' the swap file will not 122 be deleted for this buffer when Vim exits and the 123 buffer is still loaded |cpo-&|. 124 {Vi: might also exit} 125 126A Vim swap file can be recognized by the first six characters: "b0VIM ". 127After that comes the version number, e.g., "3.0". 128 129 130Links and symbolic links ~ 131 132On Unix it is possible to have two names for the same file. This can be done 133with hard links and with symbolic links (symlinks). 134 135For hard links Vim does not know the other name of the file. Therefore, the 136name of the swapfile will be based on the name you used to edit the file. 137There is no check for editing the same file by the other name too, because Vim 138cannot find the other swapfile (except for searching all of your harddisk, 139which would be very slow). 140 141For symbolic links Vim resolves the links to find the name of the actual file. 142The swap file name is based on that name. Thus it doesn't matter by what name 143you edit the file, the swap file name will normally be the same. However, 144there are exceptions: 145- When the directory of the actual file is not writable the swapfile is put 146 elsewhere. 147- When the symbolic links somehow create a loop you get an *E773* error 148 message and the unmodified file name will be used. You won't be able to 149 save your file normally. 150 151============================================================================== 1522. Recovery *recovery* *E308* *E311* 153 154Basic file recovery is explained in the user manual: |usr_11.txt|. 155 156Another way to do recovery is to start Vim and use the ":recover" command. 157This is easy when you start Vim to edit a file and you get the "ATTENTION: 158Found a swap file ..." message. In this case the single command ":recover" 159will do the work. You can also give the name of the file or the swap file to 160the recover command: 161 *:rec* *:recover* *E305* *E306* *E307* 162:rec[over] [file] Try to recover [file] from the swap file. If [file] 163 is not given use the file name for the current 164 buffer. The current contents of the buffer are lost. 165 This command fails if the buffer was modified. 166 167:rec[over]! [file] Like ":recover", but any changes in the current 168 buffer are lost. 169 170 *E312* *E309* *E310* 171Vim has some intelligence about what to do if the swap file is corrupt in 172some way. If Vim has doubt about what it found, it will give an error 173message and insert lines with "???" in the text. If you see an error message 174while recovering, search in the file for "???" to see what is wrong. You may 175want to cut and paste to get the text you need. 176 177The most common remark is "???LINES MISSING". This means that Vim cannot read 178the text from the original file. This can happen if the system crashed and 179parts of the original file were not written to disk. 180 181Be sure that the recovery was successful before overwriting the original 182file or deleting the swap file. It is good practice to write the recovered 183file elsewhere and run 'diff' to find out if the changes you want are in the 184recovered file. Or use |:DiffOrig|. 185 186Once you are sure the recovery is ok delete the swap file. Otherwise, you 187will continue to get warning messages that the ".swp" file already exists. 188 189{Vi: recovers in another way and sends mail if there is something to recover} 190 191 192ENCRYPTION AND THE SWAP FILE *:recover-crypt* 193 194When the text file is encrypted the swap file is encrypted as well. This 195makes recovery a bit more complicated. When recovering from a swap file and 196encryption has been used, you will be asked to enter one or two crypt keys. 197 198If the text file does not exist you will only be asked to enter the crypt key 199for the swap file. 200 201If the text file does exist, it may be encrypted in a different way than the 202swap file. You will be asked for the crypt key twice: 203 204 Need encryption key for "/tmp/tt" ~ 205 Enter encryption key: ****** ~ 206 "/tmp/tt" [crypted] 23200L, 522129C ~ 207 Using swap file "/tmp/.tt.swp" ~ 208 Original file "/tmp/tt" ~ 209 Swap file is encrypted: "/tmp/.tt.swp" ~ 210 If you entered a new crypt key but did not write the text file, ~ 211 enter the new crypt key. ~ 212 If you wrote the text file after changing the crypt key press enter ~ 213 to use the same key for text file and swap file ~ 214 Enter encryption key: ~ 215 216You can be in one of these two situations: 217 2181. The encryption key was not changed, or after changing the key the text file 219 was written. You will be prompted for the crypt key twice. The second 220 time you can simply press Enter. That means the same key is used for the 221 text file and the swap file. 2222. You entered a new encryption key, but did not save the text file. Vim will 223 then use the new key for the swap file, and the text file will still be 224 encrypted with the old key. At the second prompt enter the new key. 225 226Note that after recovery the key of the swap file will be used for the text 227file. Thus if you write the text file, you need to use that new key. 228 229 230 vim:tw=78:ts=8:ft=help:norl: 231