Ubuntu – Download executable script from GitHub preserving +x permissions

curlgitgithubpermissionswget

I want to make a GitHub repository of all relevant scripts I posted here as answers.

But to keep it ultimately simple for the users, I would like to give them a single command to download the script file from my repository directly, without having to install git first to git clone the entire repository.

I know I can use wget to download a single file, but when I use the "Raw" link of a file (e.g. https://github.com/AskUbuntu-Answers/dupe-check/raw/master/dupe-check), the file will get default umask permissions and therefore has no execution bit set. But I don't want that the user still has to run chmod +x.

The script files are committed pushed to the repository with correct execution bits, they are also preserved when I use git clone to get the entire repository.

What is the simplest way to retrieve (and sometimes automatically execute) a single file from GitHub preserving its executing permission without having to install git and cloning the entire repository?

Best Answer

Get the tarballs!

Even though Github doesn't expose this in the site (apparently they did ages ago), they provide tar.gz files of the repositories.

wget -qO - https://github.com/<user>/repo>/archive/master.tar.gz | tar zx --strip-components=1 <repo>-master/<filename>

<user>, <repo>, <filename> are what you'd expect them to be. --strip-components is use to prevent tar from creating a directory named after the repo.

Therefore:

$ wget -O - https://github.com/au-answers/dupe-check/archive/master.tar.gz | tar zx --strip-components=1 dupe-check-master/dupe-check
--2016-04-25 08:28:50--  https://github.com/au-answers/dupe-check/archive/master.tar.gz
Resolving github.com (github.com)... 192.30.252.128
Connecting to github.com (github.com)|192.30.252.128|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://codeload.github.com/au-answers/dupe-check/tar.gz/master [following]
--2016-04-25 08:28:51--  https://codeload.github.com/au-answers/dupe-check/tar.gz/master
Resolving codeload.github.com (codeload.github.com)... 192.30.252.160
Connecting to codeload.github.com (codeload.github.com)|192.30.252.160|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2470 (2.4K) [application/x-gzip]
Saving to: ‘STDOUT’

-                                                           100%[========================================================================================================================================>]   2.41K  --.-KB/s    in 0s      

2016-04-25 08:28:52 (21.5 MB/s) - written to stdout [2470/2470]

$ ll dupe-check 
-rwxr-xr-x 1 muru muru 7.5K Mar  5 21:46 dupe-check

I'm not convinced this is a particularly friendly way. An additional chmod +x is IMO infinitely preferable.

Failed attempts

Get the zips!

You can process substitution on zsh to extract the zips linked on the Github repo page. Github, thankfully, adds extra metadata to zips so that permissions are preserved. unzip on Ubuntu is able to use that to restore permissions. So:

unzip -j =(wget -O - https://github.com/au-answers/dupe-check/archive/master.zip) dupe-check-master/dupe-check

Unfortunately, =() is a zsh thing. It creates a proper file instead of a FIFO. Bash doesn't have an equivalent. <() is always FIFO.

Git single files

You can get a single file from repo using git. However, Github doesn't support this.

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