Essentially, I am looking for a GNU/Linux tool, that could recursively iterate through two directories, find file changes/additions/deletions; and for all changed files, output a diff. This can already be done by
diff efficiently for text files, but not for large binary files - I would like also efficient "diffs" between binary files included in the final patch (which, I gather, is known as Binary delta compression - Wikipedia as subset of Delta encoding - Wikipedia). Or, in other words, do something like described in this "wishlist" comment (from CommandLineSyntax - xdelta - Google Project Hosting):
It would be very nice if xdelta supported multiple files patching. Something like:
xdelta3 -r /path/folder1 /path/folder2 >allfilesrecursivepatch.xdelta
For recursive comparing all files on folder1 and folder2 and creating a single patch-file for all of them. And:
xdelta3 -r -d /path/folder1 <allfilesrecursivepatch.xdelta
For applying the patch on all files contained on folder1
This facility does not exist, judging by Issue 21 - xdelta - Recursive directory diff support - Google Project Hosting), although there are ways around: the issue page has several suggestions for script wrappers, but I'd rather keep things self-contained in a single tool.
Most important for me would be the patching a "live" filesystem directory part as shown above, due to my intended use case - described in more detail below, and illustrated with a
bash script that uses
I'd want to be able to update a static website on a cheapish Linux host/webfarm, which only allows FTP transfer (so no
rsync and such) with a rather low transfer speed, and only allows PHP script execution. Typically I'd need to sync from local/client/home to server/webhost, but of course I do not want to upload 200 MB each time I want to update a page
I could use outlandishideas/sync · GitHub to "Sync directory contents over HTTP using PHP", but besides only syncing from server to local, also only whole files are send: "No attempt is made to send diffs; this is not rsync". Similarly, I could use GNU FTPsync; it could probably handle file creation, modification and deletion, but it has the same problem - only whole files will be sent.
git could be used too - the below script generates directories
testdir_new, and shows that
git can encode the differences between them (in this case being "removed 1024; added 1024; modified/added 19; modified inline 1200", or total 3267 bytes of change) as a "sneakernet" git bundle file 4470 bytes in size. But even if I could persuade the host to install
git up there, I'd still have to maintain a
.git repo up on the webhost for the bundle to apply cleanly - and I definitely do not want to do that, as I couldn't spare the extra file size usage; also, it seems that managing large binary files with git - Stack Overflow requires
git annex or
git bup.. And putting around a script like below would be problematic because
git would recreate new revision hashes each time, making the bundle not apply cleanly.
Also, since in PHP, I can apparently "untar-gz without exec()? - Stack Overflow", maybe it's worth trying to determine changes in directory, then pack only the changed files in a
tar.gz, and send that to PHP script on the server, that would unpack it over the target directory. This would still send entire files, but at least they'd be compressed - but deletions on server would be difficult to handle.
Finally, the binary file diff utilities suggest that one could pack the directories in a
.tar(.gz) each, and then run the utility on those files - e.g. (via ExternalCompression - xdelta - Google Project Hosting):
gzip release-1.tar gzip release-2.tar xdelta3 -e -s release-1.tar.gz release-2.tar.gz delta-1-2.xd3 xdelta3 -d -s release-1.tar.gz delta-1-2.xd3 release-2.tar.gz
... probably also doable with JojoDiff /
jdiff archive0000.tar archive0001.tar archive0001.jdf jptch archive0000.tar archive0001.jdf archive0001b.tar
... or with
bsdiff. However, that requires me to also maintain a tar archive of the entire site on the webhost, to allow the patches to apply cleanly to it, and the space is issue here again. It would also force me to ask the webhost to allow me the install and use of at least the patching parts of the tools; and that may be worth a try again, if those tools wouldn't also require me to keep an additional tar'd copy of the site on the host.
Anyways, below is the script that demonstrates extraction of a
.bundle as a recursive diff between two directories (or rather, two versions of the same directory); relevant terminal output is included in the comments:
#!/usr/bin/env bash ## comments with double ##; (relevant) terminal output with single # ## uses git, ImageMagick, tree set -x cd /tmp rm -rf testdir export_compare mkdir testdir cd testdir git init # Initialized empty Git repository in /tmp/testdir/.git/ git config user.name "test" git config user.email "email@example.com" ## generate files - revision 1 ## - text cat /dev/urandom | tr -dc '[ -~]' | fold -w 80 -s | head -c 1024 > test_01.txt mkdir subdir cat /dev/urandom | tr -dc '[ -~]' | fold -w 80 -s | head -c 1024 > subdir/subtest_01.txt cat /dev/urandom | tr -dc '[ -~]' | fold -w 80 -s | head -c 1024 > subdir/subtest_02.txt ## - binary convert -depth 8 -size 200x150 xc:blue rgb:subdir/rgbimage.dat ## check: ## - files: tree -s --dirsfirst . # . # ├── [ 4096] subdir # │ ├── [ 90000] rgbimage.dat # │ ├── [ 1024] subtest_01.txt # │ └── [ 1024] subtest_02.txt # └── [ 1024] test_01.txt # # 1 directory, 4 files ## - view image (press "q" to quit) display -depth 8 -size 200x150 rgb:subdir/rgbimage.dat git add * git commit -m "initial commit" ## check usage du -ba --max-depth=1 . # 1024 ./test_01.txt # 96144 ./subdir # 99947 ./.git # 201211 . ## change files - revision 2 ## remove file: REP="removed 1024;" git rm subdir/subtest_02.txt ## add file REP="$REP added 1024;" cat /dev/urandom | tr -dc '[ -~]' | fold -w 80 -s | head -c 1024 > test_02.txt git add test_02.txt ## change files: ## - text: REP="$REP modified/added 19;" echo "a new changed line" >> test_01.txt ## - binary REP="$REP modified inline 1200" convert -depth 8 -size 1x200 xc:red rgb:/dev/stdout | dd of=subdir/rgbimage.dat bs=1 seek=$((200*50*3)) count=$((200*3)) conv=notrunc convert -depth 8 -size 1x200 xc:red rgb:/dev/stdout | dd of=subdir/rgbimage.dat bs=1 seek=$((200*100*3)) count=$((200*3)) conv=notrunc ## check: ## - files: tree -s --dirsfirst . # . # ├── [ 4096] subdir # │ ├── [ 90000] rgbimage.dat # │ └── [ 1024] subtest_01.txt # ├── [ 1043] test_01.txt # └── [ 1024] test_02.txt # # 1 directory, 4 files ## - view image (press "q" to quit) display -depth 8 -size 200x150 rgb:subdir/rgbimage.dat git add * git commit -m "second commit with changes" # [master 2b243fb] second commit with changes # 4 files changed, 16 insertions(+), 19 deletions(-) ... ## check usage du -ba --max-depth=1 . # 1043 ./test_01.txt # 1024 ./test_02.txt # 95120 ./subdir # 123355 ./.git # 224638 . ## go back to parent dir (/tmp) and make a new directory for "clean" exports: cd /tmp mkdir export_compare mkdir export_compare/testdir_new mkdir export_compare/testdir_old ## from git, export each revision "cleanly" cd testdir git archive HEAD | tar -x -C /tmp/export_compare/testdir_new git archive HEAD^1 | tar -x -C /tmp/export_compare/testdir_old ## create git bundle, containing the changes between new and old revision git bundle create ../commits_testdir.bundle HEAD HEAD^1 # ... Writing objects: 100% (13/13), 4.30 KiB, done. # Total 13 (delta 2), reused 0 (delta 0) ## check cd /tmp echo $REP # removed 1024; added 1024; modified/added 19; modified inline 1200 du -b commits_testdir.bundle # 4470 commits_testdir.bundle cd export_compare du -bs testdir_old testdir_new # 101264 testdir_old # 101283 testdir_new tree -s --dirsfirst . # . # ├── [ 4096] testdir_new # │ ├── [ 4096] subdir # │ │ ├── [ 90000] rgbimage.dat # │ │ └── [ 1024] subtest_01.txt # │ ├── [ 1043] test_01.txt # │ └── [ 1024] test_02.txt # └── [ 4096] testdir_old # ├── [ 4096] subdir # │ ├── [ 90000] rgbimage.dat # │ ├── [ 1024] subtest_01.txt # │ └── [ 1024] subtest_02.txt # └── [ 1024] test_01.txt # # 4 directories, 8 files # + set +x set +x