How to add multiple files to Git at the same time

To add all the changes you've made:

git add .

To commit them:

git commit -m "MY MESSAGE HERE" #-m is the message flag

You can put those steps together like this:

git commit -a -m "MY MESSAGE HERE"

To push your committed changes from your local repository to your remote repository:

git push origin master

You might have to type in your username/password for github after this. Here's a good primer on using git. A bit old, but it covers what's going on really well.

As some have mentioned a possible way is using git interactive staging. This is great when you have files with different extensions

$ git add -i
           staged     unstaged path
  1:    unchanged        +0/-1 TODO
  2:    unchanged        +1/-1 index.html
  3:    unchanged        +5/-1 lib/simplegit.rb

*** Commands ***
  1: status     2: update      3: revert     4: add untracked
  5: patch      6: diff        7: quit       8: help
What now>

If you press 2 then enter you will get a list of available files to be added:

What now> 2
           staged     unstaged path
  1:    unchanged        +0/-1 TODO
  2:    unchanged        +1/-1 index.html
  3:    unchanged        +5/-1 lib/simplegit.rb
Update>>

Now you just have to insert the number of the files you want to add, so if we wanted to add TODO and index.html we would type 1,2

Update>> 1,2
           staged     unstaged path
* 1:    unchanged        +0/-1 TODO
* 2:    unchanged        +1/-1 index.html
  3:    unchanged        +5/-1 lib/simplegit.rb
Update>>

You see the * before the number? that means that the file was added.

Now imagine that you have 7 files and you want to add them all except the 7th? Sure we could type 1,2,3,4,5,6 but imagine instead of 7 we have 16, that would be quite cumbersome, the good thing we don't need to type them all because we can use ranges,by typing 1-6

Update>> 1-6
           staged     unstaged path
* 1:    unchanged        +0/-1 TODO
* 2:    unchanged        +1/-1 index.html
* 3:    unchanged        +5/-1 lib/simplegit.rb
* 4:    unchanged        +5/-1 file4.html
* 5:    unchanged        +5/-1 file5.html
* 6:    unchanged        +5/-1 file6.html
  7:    unchanged        +5/-1 file7.html
Update>>

We can even use multiple ranges, so if we want from 1 to 3 and from 5 to 7 we type 1-3, 5-7:

Update>> 1-3, 5-7
           staged     unstaged path
* 1:    unchanged        +0/-1 TODO
* 2:    unchanged        +1/-1 index.html
* 3:    unchanged        +5/-1 lib/simplegit.rb
  4:    unchanged        +5/-1 file4.html
* 5:    unchanged        +5/-1 file5.html
* 6:    unchanged        +5/-1 file6.html
* 7:    unchanged        +5/-1 file7.html
Update>>

We can also use this to unstage files, if we type -number, so if we wanted to unstage file number 1 we would type -1:

Update>> -1
           staged     unstaged path
  1:    unchanged        +0/-1 TODO
* 2:    unchanged        +1/-1 index.html
* 3:    unchanged        +5/-1 lib/simplegit.rb
  4:    unchanged        +5/-1 file4.html
* 5:    unchanged        +5/-1 file5.html
* 6:    unchanged        +5/-1 file6.html
* 7:    unchanged        +5/-1 file7.html
Update>>

And as you can imagine we can also unstage a range of files, so if we type -range all the files on that range would be unstaged. If we wanted to unstage all the files from 5 to 7 we would type -5-7:

Update>> -5-7
           staged     unstaged path
  1:    unchanged        +0/-1 TODO
* 2:    unchanged        +1/-1 index.html
* 3:    unchanged        +5/-1 lib/simplegit.rb
  4:    unchanged        +5/-1 file4.html
  5:    unchanged        +5/-1 file5.html
  6:    unchanged        +5/-1 file6.html
  7:    unchanged        +5/-1 file7.html
Update>>

Use the git add command, followed by a list of space-separated filenames.

git add file-1 file-2 file-3

Include paths and .extensions, e.g.

git add images/logo.png scripts/app.js