git 下的(difftool)和(mergetool)是专门提供给使用者用自己的工具进行diff和merge的命令：

# git config --global  diff.tool  meld# git config --global  merge.tool meld

 

然后直接使用命令进行两次提交的比较和合并：

# git difftool HEAD HEAD^1

 

缺点：

虽然使用git difftool已经基本满足了我的需要，但还有个小问题：如果我要比较两次提交之间的差异时，difftool只能一个文件一个文件的比较，每次都要提示你是否打开这个文件，然后打开meld进行比较，当你关闭meld后，才会提示下一个差异文件。这样非常浪费效率，下面一个方法直接利用meld的目录比较能力（参考： ）：

1.新建diffall文本文件

2.在diffall文件中添加如下代码：

1 #!/bin/sh  2 # Copyright 2010 - 2012, Tim Henigan 
      
         3 #  4 # Permission is hereby granted, free of charge, to any person obtaining  5 # a copy of this software and associated documentation files (the  6 # "Software"), to deal in the Software without restriction, including  7 # without limitation the rights to use, copy, modify, merge, publish,  8 # distribute, sublicense, and/or sell copies of the Software, and to  9 # permit persons to whom the Software is furnished to do so, subject to 10 # the following conditions: 11 # 12 # The above copyright notice and this permission notice shall be included 13 # in all copies or substantial portions of the Software. 14 # 15 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 16 # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 17 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 18 # IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 19 # CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 20 # TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 21 # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 22  23  24 # Perform a directory diff between commits in the repository using 25 # the external diff or merge tool specified in the user's config. 26  27 USAGE='[--cached] [--copy-back] [-x|--extcmd=
       ] 
       
        {0,2} [-- 
        
         *] 28     --cached     Compare to the index rather than the working tree. 29     --copy-back  Copy files back to the working tree when the diff 30                  tool exits (in case they were modified by the 31                  user).  This option is only valid if the diff 32                  compared with the working tree. 33     -x=
          34     --extcmd=
           Specify a custom command for viewing diffs. 35                  git-diffall ignores the configured defaults and 36                  runs $command $LOCAL $REMOTE when this option is 37                  specified. Additionally, $BASE is set in the 38                  environment. 39 ' 40  41 SUBDIRECTORY_OK=1 42 . "$(git --exec-path)/git-sh-setup" 43  44 TOOL_MODE=diff 45 . "$(git --exec-path)/git-mergetool--lib" 46  47 merge_tool="$(get_merge_tool)" 48 if test -z "$merge_tool" 49 then 50     echo "Error: Either the 'diff.tool' or 'merge.tool' option must be set." 51     usage 52 fi 53  54 start_dir=$(pwd) 55  56 # All the file paths returned by the diff command are relative to the root 57 # of the working copy. So if the script is called from a subdirectory, it 58 # must switch to the root of working copy before trying to use those paths. 59 cdup=$(git rev-parse --show-cdup) && 60 cd "$cdup" || { 61     echo >&2 "Cannot chdir to $cdup, the toplevel of the working tree" 62     exit 1 63 } 64  65 # set up temp dir 66 tmp=$(perl -e 'use File::Temp qw(tempdir); 67     $t=tempdir("/tmp/git-diffall.XXXXX") or exit(1); 68     print $t') || exit 1 69 trap 'rm -rf "$tmp"' EXIT 70  71 left= 72 right= 73 paths= 74 dashdash_seen= 75 compare_staged= 76 merge_base= 77 left_dir= 78 right_dir= 79 diff_tool= 80 copy_back= 81  82 while test $# != 0 83 do 84     case "$1" in 85     -h|--h|--he|--hel|--help) 86         usage 87         ;; 88     --cached) 89         compare_staged=1 90         ;; 91     --copy-back) 92         copy_back=1 93         ;; 94     -x|--e|--ex|--ext|--extc|--extcm|--extcmd) 95         if test $# = 1 96         then 97             echo You must specify the tool for use with --extcmd 98             usage 99         else100             diff_tool=$2101             shift102         fi103         ;;104     --)105         dashdash_seen=1106         ;;107     -*)108         echo Invalid option: "$1"109         usage110         ;;111     *)112         # could be commit, commit range or path limiter113         case "$1" in114         *...*)115             left=${
    1%...*}116             right=${
    1#*...}117             merge_base=1118             ;;119         *..*)120             left=${
    1%..*}121             right=${
    1#*..}122             ;;123         *)124             if test -n "$dashdash_seen"125             then126                 paths="$paths$1 "127             elif test -z "$left"128             then129                 left=$1130             elif test -z "$right"131             then132                 right=$1133             else134                 paths="$paths$1 "135             fi136             ;;137         esac138         ;;139     esac140     shift141 done142 143 # Determine the set of files which changed144 if test -n "$left" && test -n "$right"145 then146     left_dir="cmt-$(git rev-parse --short $left)"147     right_dir="cmt-$(git rev-parse --short $right)"148 149     if test -n "$compare_staged"150     then151         usage152     elif test -n "$merge_base"153     then154         git diff --name-only "$left"..."$right" -- $paths >"$tmp/filelist"155     else156         git diff --name-only "$left" "$right" -- $paths >"$tmp/filelist"157     fi158 elif test -n "$left"159 then160     left_dir="cmt-$(git rev-parse --short $left)"161 162     if test -n "$compare_staged"163     then164         right_dir="staged"165         git diff --name-only --cached "$left" -- $paths >"$tmp/filelist"166     else167         right_dir="working_tree"168         git diff --name-only "$left" -- $paths >"$tmp/filelist"169     fi170 else171     left_dir="HEAD"172 173     if test -n "$compare_staged"174     then175         right_dir="staged"176         git diff --name-only --cached -- $paths >"$tmp/filelist"177     else178         right_dir="working_tree"179         git diff --name-only -- $paths >"$tmp/filelist"180     fi181 fi182 183 # Exit immediately if there are no diffs184 if test ! -s "$tmp/filelist"185 then186     exit 0187 fi188 189 if test -n "$copy_back" && test "$right_dir" != "working_tree"190 then191     echo "--copy-back is only valid when diff includes the working tree."192     exit 1193 fi194 195 # Create the named tmp directories that will hold the files to be compared196 mkdir -p "$tmp/$left_dir" "$tmp/$right_dir"197 198 # Populate the tmp/right_dir directory with the files to be compared199 while read name200 do201     if test -n "$right"202     then203         ls_list=$(git ls-tree $right "$name")204         if test -n "$ls_list"205         then206             mkdir -p "$tmp/$right_dir/$(dirname "$name")"207             git show "$right":"$name" >"$tmp/$right_dir/$name" || true208         fi209     elif test -n "$compare_staged"210     then211         ls_list=$(git ls-files -- "$name")212         if test -n "$ls_list"213         then214             mkdir -p "$tmp/$right_dir/$(dirname "$name")"215             git show :"$name" >"$tmp/$right_dir/$name"216         fi217     else218         if test -e "$name"219         then220             mkdir -p "$tmp/$right_dir/$(dirname "$name")"221             cp "$name" "$tmp/$right_dir/$name"222         fi223     fi224 done < "$tmp/filelist"225 226 # Populate the tmp/left_dir directory with the files to be compared227 while read name228 do229     if test -n "$left"230     then231         ls_list=$(git ls-tree $left "$name")232         if test -n "$ls_list"233         then234             mkdir -p "$tmp/$left_dir/$(dirname "$name")"235             git show "$left":"$name" >"$tmp/$left_dir/$name" || true236         fi237     else238         if test -n "$compare_staged"239         then240             ls_list=$(git ls-tree HEAD "$name")241             if test -n "$ls_list"242             then243                 mkdir -p "$tmp/$left_dir/$(dirname "$name")"244                 git show HEAD:"$name" >"$tmp/$left_dir/$name"245             fi246         else247             mkdir -p "$tmp/$left_dir/$(dirname "$name")"248             git show :"$name" >"$tmp/$left_dir/$name"249         fi250     fi251 done < "$tmp/filelist"252 253 LOCAL="$tmp/$left_dir"254 REMOTE="$tmp/$right_dir"255 256 if test -n "$diff_tool"257 then258     export BASE259     eval $diff_tool '"$LOCAL"' '"$REMOTE"'260 else261     run_merge_tool "$merge_tool" false262 fi263 264 # Copy files back to the working dir, if requested265 if test -n "$copy_back" && test "$right_dir" = "working_tree"266 then267     cd "$start_dir"268     git_top_dir=$(git rev-parse --show-toplevel)269     find "$tmp/$right_dir" -type f |270     while read file271     do272         cp "$file" "$git_top_dir/${file#$tmp/$right_dir/}"273     done274 fi
        
       
      

3.保存，运行如下命令配置

# git config --global alias.diffall /PATH/diffall