Wow, that’s five possible versions.<\/p>\n\n\n\n
Scene: Ray sips at a glass of bourbon, and types furiously, making changes to Chapter 1. He saves his work periodically.<\/em><\/p>\n\n\n\n While Ray is accessing his muse, let’s learn about Git’s diff<\/strong> tool:<\/p>\n\n\n\n The Git diff<\/strong> command is a tool we can use to compare different versions of source files:<\/p>\n\n\n\n This produces a report of changes needed to make “target” look like “source”. There are some more common, special cases:<\/p>\n\n\n\n To make <target> look like the working tree<\/strong>:<\/p>\n\n\n\n To make <target> look like the staging area<\/strong>:<\/p>\n\n\n\n What would git commit -a<\/strong> do? Find out with:<\/p>\n\n\n\n What would git commit<\/strong> do? Find out with:<\/p>\n\n\n\n Consider the following sequence:<\/p>\n\n\n\n We’ve now got different versions of source.txt in all possible locations. Let’s find out the differences:<\/p>\n\n\n\n Yup, that describes how to update the staging area<\/strong> to match the version in the working tree<\/strong>. (From here on out, I’ll omit the first few lines of the diff output).<\/p>\n\n\n\n Exercise for the student: Try out the other variations.<\/p>\n\n\n\n Cut scene: Editors office. Penny White is sitting at her computer.<\/em><\/p>\n\n\n\n Penny cloned the repository yesterday, but she’s pretty sure they’ll be some updates from Ray on the server:<\/p>\n\n\n\n Penny could merge<\/strong> at this point, but before she does, she’d like to see what the changes are.<\/p>\n\n\n\n From our experiments above, we know that in order to see what will change during the merge, Penny will need to request a diff using “master” as the <target> and “origin\/master” as the <source>:<\/p>\n\n\n\n Ray has been busy. The first thing Penny is going to do after merging is correct the spelling of “silhouette”.<\/p>\n\n\n\n Penny is not a fan of the text output from diff, so she has read up on the difftool<\/strong> command. It is essentially identical to diff<\/strong>, except Git will launch your preferred graphical utility to display the diff information.<\/p>\n\n\n\n If you’re interacting with source code from inside an IDE that includes Git integration, this probably won’t be something you’ll need to do. But it helps to understand what is going on behind the scenes.<\/p>\n\n\n\n I recommend meld<\/strong>, as it is reviewed positively and has versions for both Windows and Linux: https:\/\/meldmerge.org\/<\/a><\/p>\n\n\n\n After we’ve installed it, we can enable it in Git by adding the following lines to .gitconfig:<\/p>\n\n\n Penny views the changes using Meld:<\/p>\n\n\n\n Meld presents each changed file in a separate window, opening them in sequence as the previous one is closed. For many files, this can get clumsy.<\/p>\n\n\n\n An alternative would be to generate a list of files with differences, then launch the difftool for each file on your own schedule:<\/p>\n\n\n\n That last command demonstrates how Penny would specify a single file, using the “branch_path:file_spec” notation.<\/p>\n\n\n\n That’s all for this Appendix. Go back to the article here.<\/p>\n","protected":false},"excerpt":{"rendered":" Ray is writing the next great American detective novel, and we’ve started by creating a remote BitBucket Git repository to manage his changes. Ray clones the repository: $ git clone https:\/\/ray-chandler@bitbucket.org\/ray-chandler\/noir.git Consider that Ray now has a tracking branch called “master”; a remote reference called “origin”; and a remote-tracking branch “origin\/master”. He has many possible […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-396","post","type-post","status-publish","format-standard","hentry","category-source-control","post-preview"],"_links":{"self":[{"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/posts\/396","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/comments?post=396"}],"version-history":[{"count":0,"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/posts\/396\/revisions"}],"wp:attachment":[{"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/media?parent=396"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/categories?post=396"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spacefold.com\/colin\/morethanfour\/wp-json\/wp\/v2\/tags?post=396"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Using DIFF<\/h3>\n\n\n\n
$ git diff <target> <source> # <\/pre>\n\n\n\n
$ git diff # target = staging area\n$ git diff HEAD # target = HEAD \n$ git diff <target> <\/pre>\n\n\n\n
$ git diff --staged # target = HEAD\n$ git diff --staged HEAD # target = HEAD \n$ git diff --staged <target><\/pre>\n\n\n\n
$ git diff --staged HEAD<\/pre>\n\n\n\n
$ git diff --staged<\/pre>\n\n\n\n
Examples<\/h4>\n\n\n\n
echo \"This line is pushed to remote\/master.\" > source.txt\ngit commit -a -m \"Step1\"\ngit push origin\ngit switch -c secundo\necho \"This line is committed to secundo.\" > source.txt\ngit commit -a -m \"Step2\"\ngit switch master\necho \"This line is committed to master.\" > source.txt\ngit commit -a -m \"Step3\"\necho \"This line is in the staging area.\" > source.txt\ngit add source.txt\necho \"This line is in the working tree.\" > source.txt<\/pre>\n\n\n\n
$ git diff<\/pre>\n
diff --git a\/source.txt b\/source.txt\nindex 16f0b21..c260d9d 100644\n--- a\/source.txt\n+++ b\/source.txt\n@@ -1 +1 @@\n-This line is in the staging area.\n+This line is edited in the working tree.<\/pre>\n\n\n\n
$ git diff --staged origin\/master<\/pre>\n
:\n-This line is pushed to remote\/master.\n+This line is in the staging area.<\/pre>\n\n
$ git diff secundo master<\/pre>\n
:\n-This line is committed to secundo.\n+This line is committed to master.<\/pre>\n\n\n\n
Back to that detective story<\/h3>\n\n\n\n
$ git fetch origin<\/pre>\n
:\nUnpacking objects: 100% (6\/6), 738 bytes | 22.00 KiB\/s, done.\nFrom https:\/\/bitbucket.org\/ray-chandler\/noir\n 14c6528..713d32a master -> origin\/master<\/pre>\n\n
$ git status<\/pre>\n
On branch master\nYour branch is behind 'origin\/master' by 2 commits, and can be fast-forwarded.\n (use \"git pull\" to update your local branch)\nnothing to commit, working tree clean<\/pre>\n\n\n\n
$ git diff master origin\/master<\/pre>\n
diff --git a\/detective.txt b\/detective.txt\nindex df79c59..8616f4d 100644\n--- a\/detective.txt\n+++ b\/detective.txt\n@@ -1,7 +1,9 @@\n Chapter 1\n\n There was a knock at the door. I quickly hid the comic book under the WIRED magazine\n-and took out some official looking papers and scattered them about the desk.\n+on the desk and took out some official looking papers and scattered them about.\n\n \"Jess!\" I yelled.\n\n+The door opened. The siloette blocking the light from the door was a dame,\n+but it wasn't Jess.<\/pre>\n\n\n\n
A Graphical Diff<\/h3>\n\n\n\n
\n[diff]\n tool = meld\n[difftool "meld"]\n path = meld ; Windows: c:\\\\Program Files (x86)\\\\Meld\\Meld.exe\n[difftool]\n prompt=false\n\n[merge]\n tool = meld\n[mergetool "meld"]\n path = meld ; Windows: c:\\\\Program Files (x86)\\\\Meld\\Meld.exe\n[mergetool]\n keepBackup = false\n<\/pre><\/div>\n\n\n
$ git difftool master origin\/master<\/pre>\n\n\n\n
![\"\"](\"http:\/\/spacefold.com\/colin\/morethanfour\/wp-content\/uploads\/2021\/09\/image-1024x309.png\")
$ git diff --compact-summary master origin\/master<\/pre>\n
detective.txt | 7 ++-----\n references.txt | 1 -\n 2 files changed, 2 insertions(+), 6 deletions(-)\n<\/pre>\n\n
$ git difftool master:detective.txt origin\/master:detective.txt<\/pre>\n\n\n\n
Further reading:<\/h4>\n\n\n\n