Use shlex to split custom vim command

This allows to include spaces in vim command
Add example to change default diff algorithm
Move to first line on each file

Backport from da5e24260

README.md

@@ -1,3 +1,27 @@
+Do you use `git difftool` to review changes before making a commit? The problem with that is that you get to see the diff of one file at a time. You can't easily stop it after few files and you can't go back to a previous file. `vimtabdiff.py` loads all the files with diffs, one in each vim tab page. You can move around any file and edit the diffs easily.
+
+
+# Install
+
+```bash
+    mkdir -p ~/bin
+
+    # for python version >= 3.10
+    curl -o ~/bin/vimtabdiff.py "https://raw.githubusercontent.com/balki/vimtabdiff/master/vimtabdiff.py"
+
+    # for python version < 3.10
+    curl -o ~/bin/vimtabdiff.py "https://raw.githubusercontent.com/balki/vimtabdiff/py38/vimtabdiff.py"
+
+    chmod +x ~/bin/vimtabdiff.py
+```
+
+You may need to add `~/bin` to your PATH variable if not already done. See [here](https://wiki.archlinux.org/title/Environment_variables#Per_user) for help.
+👍 this [issue](https://github.com/balki/vimtabdiff/issues/1) for `pip install` support 
+
+
+# Screenshot
+![image](https://user-images.githubusercontent.com/189196/206880555-c71b472c-144c-4c82-a4ab-f8a4fd36f7a5.png)
+
 # Usage
 ```help
     usage: vimtabdiff.py [-h] [--vim VIM] pathA pathB
@@ -34,6 +58,7 @@
 
 ## Using custom vim command
 
+Using clean vim without reading `vimrc`
 ```bash
     git config --global difftool.vimtabdiff.cmd 'vimtabdiff.py --vim "vim --clean" $LOCAL $REMOTE'
 ```
@@ -47,16 +72,14 @@ Git config file (`~/.gitconfig`) should look like this
     [difftool "vimtabdiff"]
             cmd = vimtabdiff.py --vim \"vim --clean\" $LOCAL $REMOTE
 ```
+Using better diff algorithm
 
+```bash
+    git config --global difftool.vimtabdiff.cmd 'vimtabdiff.py --vim "vim +\"set diffopt+=algorithm:patience\"" $LOCAL $REMOTE'
 
-# Known issues
+```
 
-  1. If your path to custom vim has space, it does not work. i.e. Following does *not* work
-
-      ```bash
-      git config --global difftool.vimtabdiff.cmd 'vimtabdiff.py --vim "/home/foo/my files/bin/vim" $LOCAL $REMOTE'
-      ```
-  2. Not tested in non-linux OS. Pull requests welcome if found any issues.
+*Note:* Not tested in non-linux OS. But I guess it should work fine. Pull requests welcome if found any issues.
 
 # Similar
 

vimtabdiff.py

@@ -6,7 +6,7 @@ import pathlib
 import itertools
 import tempfile
 import subprocess
-
+import shlex
 
 def star(f):
     """ see https://stackoverflow.com/q/21892989 """
@@ -15,7 +15,8 @@ def star(f):
 
 def parse_args():
     parser = argparse.ArgumentParser(
-        description="Show diff of files from two directories in vim tabs")
+        description="Show diff of files from two directories in vim tabs",
+        epilog="See https://github.com/balki/vimtabdiff for more info")
     parser.add_argument("pathA")
     parser.add_argument("pathB")
     parser.add_argument("--vim", help="vim command to run", default="vim")
@@ -76,7 +77,7 @@ def main():
             aPath = a.resolve() if a else os.devnull
             bPath = b.resolve() if b else os.devnull
             print(
-                f"tabedit {aPath} | diffthis | vsp {bPath} | diffthis | diffupdate",
+                f"tabedit {aPath} | vsp {bPath}",
                 file=vimCmdFile)
         cmds = f"""
         let &splitright = s:spr
@@ -87,7 +88,7 @@ def main():
         call delete("{vimCmdFile.name}")
         """
         print(cmds, file=vimCmdFile)
-    subprocess.run(args.vim.split() + ["-S", vimCmdFile.name])
+    subprocess.run(shlex.split(args.vim) + ["-S", vimCmdFile.name])
 
 
 if __name__ == '__main__':