provide an option to install all dotfiles to a temporary directory

README.md

@@ -272,6 +272,10 @@ $ dotdrop.sh compare
 The diffing is done by diff in the backend, one can provide specific
 options to diff using the `-o` switch.
 
+It is also possible to install all dotfiles for a specific profile
+in a temporary directory in order to manually compare them with
+the local version by using `install` and the `-t` switch.
+
 ## Import dotfiles
 
 Dotdrop allows to import dotfiles directly from the
@@ -477,16 +481,37 @@ $ sudo pip3 install dotdrop --upgrade
 ## Update dotfiles
 
 Dotfiles managed by dotdrop can be updated using the `update` command.
+
 There are two cases:
 
-  * the dotfile doesn't use [templating](#template): the new version of the dotfile is copied to the
+**The dotfile doesn't use [templating](#template)**
-    *dotfiles* directory and overwrites the old version. If git is used to version the dotfiles stored
-    by dotdrop, the git command `diff` can be used to view the changes.
-  * the dotfile uses [templating](#template): the dotfile must be manually updated, the use of
-    the dotdrop command `compare` can be helpful to identify the changes to apply to the template.
 
-```
+The new version of the dotfile is copied to the *dotfiles* directory and overwrites
+the old version. If git is used to version the dotfiles stored by dotdrop, the git command
+`diff` can be used to view the changes.
+
+```bash
 $ dotdrop.sh update ~/.vimrc
+$ git diff
+```
+
+**The dotfile uses [templating](#template)**
+
+The dotfile must be manually updated, two solutions can be used to identify the
+changes to apply to the template:
+
+* Use dotdrop's `compare` command
+* Install the dotfiles to a temporary directory (using the `install` command and the
+  `-t` switch) and compare the generated dotfile with the local one.
+
+```bash
+# use compare to identify change(s)
+$ ./dotdrop.sh compare --files=~/.vimrc
+
+# use install to identify change(s)
+$ ./dotdrop.sh install -t
+Installed to tmp /tmp/dotdrop-6kix7555
+$ diff ~/.vimrc /tmp/dotdrop-6kix7555/home/user/.vimrc
 ```
 
 ## Store sensitive dotfiles

dotdrop/dotdrop.py

@@ -41,7 +41,7 @@ USAGE = """
 {}
 
 Usage:
-  dotdrop install   [-fndVb] [-c <path>] [-p <profile>]
+  dotdrop install   [-tfndVb] [-c <path>] [-p <profile>]
   dotdrop import    [-ldVb]   [-c <path>] [-p <profile>] <paths>...
   dotdrop compare   [-Vb]     [-c <path>] [-p <profile>]
                               [-o <opts>] [-i <name>...]
@@ -59,6 +59,7 @@ Options:
   -i --ignore=<name>      File name to ignore when diffing.
   -o --dopts=<opts>       Diff options [default: ].
   -n --nodiff             Do not diff when installing.
+  -t --temp               Install to a temporary directory for review.
   -l --link               Import and link.
   -f --force              Do not warn if exists.
   -V --verbose            Be verbose.
@@ -74,7 +75,7 @@ Options:
 ###########################################################
 
 
-def install(opts, conf):
+def install(opts, conf, temporary=False):
     """install all dotfiles for this profile"""
     dotfiles = conf.get_dotfiles(opts['profile'])
     if dotfiles == []:
@@ -83,10 +84,13 @@ def install(opts, conf):
         return False
     t = Templategen(opts['profile'], base=opts['dotpath'],
                     variables=opts['variables'], debug=opts['debug'])
+    tmpdir = None
+    if temporary:
+        tmpdir = get_tmpdir()
     inst = Installer(create=opts['create'], backup=opts['backup'],
                      dry=opts['dry'], safe=opts['safe'], base=opts['dotpath'],
                      workdir=opts['workdir'], diff=opts['installdiff'],
-                     debug=opts['debug'])
+                     debug=opts['debug'], totemp=tmpdir)
     installed = []
     for dotfile in dotfiles:
         if dotfile.actions and Cfg.key_actions_pre in dotfile.actions:
@@ -126,6 +130,8 @@ def install(opts, conf):
                             LOG.dbg('executing post action {}'.format(action))
                         action.execute()
         installed.extend(r)
+    if temporary:
+        LOG.log('\nInstalled to tmp {}.'.format(tmpdir))
     LOG.log('\n{} dotfile(s) installed.'.format(len(installed)))
     return True
 
@@ -154,7 +160,6 @@ def apply_trans(opts, dotfile):
 
 
 def _select(selections, dotfiles):
-    ret = True
     selected = []
     for selection in selections:
         df = next(
@@ -166,8 +171,7 @@ def _select(selections, dotfiles):
             selected.append(df)
         else:
             LOG.err('no dotfile matches \"{}\"'.format(selection))
-            ret = False
+    return selected
-    return selected, ret
 
 
 def compare(opts, conf, tmp, focus=None, ignore=[]):
@@ -181,7 +185,7 @@ def compare(opts, conf, tmp, focus=None, ignore=[]):
     same = True
     selected = dotfiles
     if focus:
-        selected, ret = _select(focus.replace(' ', '').split(','), dotfiles)
+        selected = _select(focus.replace(' ', '').split(','), dotfiles)
 
     if len(selected) < 1:
         return False
@@ -362,13 +366,14 @@ def main():
 
         elif args['install']:
             # install the dotfiles stored in dotdrop
-            ret = install(opts, conf)
+            ret = install(opts, conf, temporary=args['--temp'])
 
         elif args['compare']:
             # compare local dotfiles with dotfiles stored in dotdrop
             tmp = get_tmpdir()
             opts['dopts'] = args['--dopts']
-            ret = compare(opts, conf, tmp, args['--files'], args['--ignore'])
+            ret = compare(opts, conf, tmp, focus=args['--files'],
+                          ignore=args['--ignore'])
             if os.listdir(tmp):
                 LOG.raw('\ntemporary files available under {}'.format(tmp))
             else:

dotdrop/installer.py

@@ -20,7 +20,7 @@ class Installer:
 
     def __init__(self, base='.', create=True, backup=True,
                  dry=False, safe=False, workdir='~/.config/dotdrop',
-                 debug=False, diff=True):
+                 debug=False, diff=True, totemp=None):
         self.create = create
         self.backup = backup
         self.dry = dry
@@ -29,6 +29,7 @@ class Installer:
         self.base = base
         self.debug = debug
         self.diff = diff
+        self.totemp = totemp
         self.comparing = False
         self.log = Logger()
 
@@ -36,6 +37,8 @@ class Installer:
         """install the src to dst using a template"""
         src = os.path.join(self.base, os.path.expanduser(src))
         dst = os.path.expanduser(dst)
+        if self.totemp:
+            dst = self._pivot_path(dst, self.totemp)
         if utils.samefile(src, dst):
             # symlink loop
             self.log.err('dotfile points to itself: {}'.format(dst))
@@ -50,6 +53,8 @@ class Installer:
         """set src as the link target of dst"""
         src = os.path.join(self.base, os.path.expanduser(src))
         dst = os.path.expanduser(dst)
+        if self.totemp:
+            return self.install(templater, src, dst)
 
         if Templategen.is_template(src):
             if self.debug: