Wikia

Vim Tips Wiki

Swap file "..."already exists! - so diff it

Talk0
1,612pages on
this wiki
Revision as of 19:46, July 3, 2013 by Fritzophrenic (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Tip 1517 Printable Monobook Previous Next

created 2007 · complexity intermediate · author Richard Bronosky · version 7.0


When opening a file (in this example geocode.py) in Vim, I regularly encounter messages like:

E325: ATTENTION
Found a swap file by the name ".geocode.py.swp"
          owned by: rbronosky   dated: Fri Sep  7 17:17:37 2007
         file name: geocode.py
          modified: YES
         user name: rbronosky
        process ID: 6490
While opening file "geocode.py"
             dated: Fri Sep  7 17:17:04 2007
(1) Another program may be editing the same file.
    If this is the case, be careful not to end up with two
    different instances of the same file when making changes.
    Quit, or continue with caution.
(2) An edit session for this file crashed.
    If this is the case, use ":recover" or "vim -r geocode.py"
    to recover the changes (see ":help recovery").
    If you did this already, delete the swap file ".geocode.py.swp"
    to avoid this message.
Swap file ".geocode.py.swp" already exists!
[O]pen Read-Only, (E)dit anyway, (R)ecover, (D)elete it, (Q)uit, (A)bort:

This is the result of not properly closing an open buffer, usually because of a lost ssh connection. If there were unsaved changes, they can be recovered from this swap file. In order to know if this swap file is of value to me, I need to do some investigating. I have developed a system for resolving this quickly with as few keystrokes as possible.

  1. r # at the prompt hit "r" to recover the swap file
  2.  :sav! /tmp/%
  3.  :vs
  4.  :diffthis
  5. CTRL-W_l
  6.  :bp
  7. e # at the prompt hit "e" to edit anyway
  8.  :diffthis

The result will be a vertically split screen with the swap file on the left and the regular file on the right. You will be in diff mode and if the files are identical they will both be folded into one line.

Sure, this would make a good script, but I am a big fan of "learn to do it by hand". That way you can do it on any system, and you can use each of the little steps to aid your daily vimming.

If you want to know more about the commands used, use :help, for example:

See alsoEdit

CommentsEdit

Losing swapfiles Edit

After recovering a file from a swapfile and deleting the swapfile you will usually use swapname .swo (or similar). If something goes wrong again, vim will not detect the .swo swapfile on startup. It is useful to restart vim, or do the following trick:

:set swf!|set swf!

In this way vim will delete the .swo swapfile and make a new one ending with.swp (you can check this with :swapname command). Now you are completely safe.


Automatically deleting redundant swapfiles with a shellscript Edit

This is a useful trick, but it would be better if it was automated. Also in the situation where the recovered swapfile turns out to be identical to the real file, there is no need for the diffing. I use a shellscript to help deal with swapfiles, before starting Vim:

# Expects variables realfile, swapfile, recoveryfile.
vim -r "$swapfile" -c ":wq! $recoveryfile" && rm "$swapfile"
if cmp "$recoveryfile" "$realfile"
then rm "$recoveryfile"
else vimdiff "$recoveryfile" "$realfile"
fi


Quick comparison with a little plugin Edit

Instead of steps 2-8 above, I do a quick comparison with:

2. :DiffAgainstFileOnDisk

And after that I do :e<Enter>d to delete the swapfile, or :w! to overwrite the file.

For this shortcut you will need a system with diff, and this script in ~/.vim/plugin/diff_against_file_on_disk.vim

command! DiffAgainstFileOnDisk call DiffAgainstFileOnDisk()

function! DiffAgainstFileOnDisk()
  :w! /tmp/working_copy
  exec "!diff /tmp/working_copy %"
endfunction


Feature Request Edit

For goodness sake, if the swapfile is identical to the file on disk, then Vim should just automatically drop it for us, and not give us a prompt at all...


Bash function to help handle swap files Edit

I sometimes get lots of swap files when my laptop loses power whlie vim is open. Using the above tips I created a bash function to help. It checks to see if the swap file is being used by an active vim process and if it isn't, it recovers the swap file into a recovery file (leaving the original file in place). It then compares the original file against recovered file; if they are identical it automatically removes the recovered file and swap file. If the recovered file and original file aren't the same, but the original file is newer than the swap file it asks if the user if they want to just delete the recovered file, or if they want to view a diff. If the swap file is newer than the original file and the recovered file is different than the original file, then vimdiff is opened so you can move any differences into the original file. When vimdiff is exited the function cleans up the old swap file and recovered file.

function vim-process-swap {
    local swapfile_first=0
    while true; do
        case "$1" in
            ""|-h|--help)
                echo "usage: vim-process-swap file [swapfile [recoverfile]]" >&2
                return 1;;
            -s)
                shift
                swapfile_first=1;;
            *)
                break;;
        esac
    done
    local realfile=`readlink -f "$1"`
    local path=`dirname "$realfile"`
    local realname=`basename "$realfile"`
    if [ $swapfile_first -eq 1 ]; then
        local swapfile=$realfile
        realname=${realname:1:-4}
        realfile="${path}/${realname}"
    else
        local swapfile=${2:-"${path}/.${realname}.swp"}
    fi
    local recoverfile=${3:-"${path}/${realname}-recovered"}
    local lastresort=0
    for f in "$realfile" "$swapfile"; do
        if [ ! -f "$f" ]; then
            echo "File $f does not exist." >&2
            return 1
        elif fuser "$f"; then
            echo "File $f in use by process." >&2
            return 1
        fi
    done
    if [ -f "$recoverfile" ]; then
        echo "Recover file $recoverfile already exists. Delete existing recover file first." >&2
        return 1
    fi
    vim -u /dev/null --noplugin -r "$swapfile" -c ":wq $recoverfile"
    if cmp -s "$realfile" "$recoverfile"; then
        rm "$swapfile" "$recoverfile"
    elif [ "$realfile" -nt "$swapfile" ] && [ `stat -c%s "$realfile"` -gt `stat -c%s "$recoverfile"` ]; then
        echo "Swapfile is older than realfile, and recovered file is smaller than realfile"
        if _prompt_yn "Delete recovered file and swapfile without doing diff?"; then
            rm "$swapfile" "$recoverfile"
        else
            lastresort=1
        fi
    else
        lastresort=1
    fi
 
    if [[ "$lastresort" -ne 0 ]]; then
        rm "$swapfile"
        vimdiff "$recoverfile" "$realfile"
        if _prompt_yn "Delete recovered file?"; then
            rm "$recoverfile"
        fi
    fi
 
}
 
function _prompt_yn {
    while true; do
        read -p "$1 [y|n] " yn
        case $yn in
            [Yy]* ) return 0;;
            [Nn]* ) return 1;;
            * ) echo "Please answer yes or no.";;
        esac
    done
}

Usage is simple: vim-process-swap file [swapfile [recoverfile]] swapfile and recoverfile are optional.

If you are using the function in a loop over swap files, you can use the script like so: vim-process-swap -s $swapfile and you won't need to pass the real filename. Note that when using the -s flag that it isn't possible to specify a recoveryfile name or location.

Around Wikia's network

Random Wiki