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Accepted
Alexey Timanovsky
Asked: 2009-08-27 09:17:20 +0800 CST

How do diff over ssh?

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How do I diff files/folders across machines provided that the only connectivity available is ssh?

ssh

16 Answers

  1. You can do it with Bash's process substitution:

     diff foo <(ssh myServer 'cat foo')

    Or, if both are on remote servers:

    diff <(ssh myServer1 'cat foo') <(ssh myServer2 'cat foo')
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  2. Best Answer

    Finally I've found great solution: vimdiff

    vimdiff /path/to/file scp://remotehost//path/to/file

    thanks to http://linux.spiney.org/remote_diff_with_vim_and_ssh see also http://www.vim.org/scripts/script.php?script_id=1075 .

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  3. If you just want to see what files are different, rather than a diff of the actual files, then you can use rsync --dry-run

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  4. Here's another quick and dirty command line recipe. Unlike the chosen answer, it works inside of makefiles:

    ssh [login]@[host] "cat [remote file]" | diff - "[local file]"
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  5. Use scp to bring the files to a common machine and diff them there?

    Or, if you just want to know if the files are different or not, hash them with md5sum on each machine.

    You could also look into something like SSHFS, but I don't know how well an algorithm like diff performs over that.

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  6. One way, if it is possible on your system would be to simply mount the remote filesystem with sshfs.

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  7. You can use rsync in dry run mode, as suggested briefly in another answer. It lists any files that are different.

    For that, use the rvnc options (r=recursive, v=verbose, n= dry-run, c=checksum). With rsync in pull mode (rsync [OPTION...] [USER@]HOST:SRC... [DEST]), an example is:

    rsync -rvnc [email protected]:/var/www/html/dev/ .

    Remember, this provides no info on whether the local or remote file is newer. Just if they differ.

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    • on your local machine, make a recursive copy of the directory you want to diff. For instance:

      cp -R dir replica

    • use rsync to replicate the remote directory over the local copy:

       rsync remote:/path/to/dir replica

    • use diff to find difference between the local directory and the local replica of the remote one:

      diff dir replica
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  9. If you have sshfs and need to diff directories:

    mkdir remote_path
sshfs user@host:/path/ remote_path
diff -r path remote_path
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  10. Here is how I did it.

    I used SFTP to the remote server and entered my username/pwd when prompted. Then I used the dir that was created in the .gvfs dir in my home directory in the diff command.

    diff -r --brief /home/user dir/.gvfs/SFTP\ on\ freenas.local/path to dir/dir1 /path to local dir/dir2
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