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In the previous video, we staged
a change to medals.html that added

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a heading announcing a 100% off sale.

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We decided that it was a bad idea,
so we unstaged the change.

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But the medals.html file saved in our
working directory still has that 100% off

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heading.

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Now, this change is small enough
that it would be easy to go in and

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remove manually.

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But in a more complex project,
the change could affect dozens of lines.

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That's why git offers a command to
discard changes to a file automatically.

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By the way,

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remember how in an earlier video I said
git can undo almost any mistake you make?

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We're about to show you
something git can't undo.

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The changes in the medals.html
have never been committed, so

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git doesn't have them stored anywhere.

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And we're about to erase those changes.

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When you're discarding changes
to a modified file, make

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absolutely sure that you're not discarding
changes you actually wanted to keep.

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Okay, with that warning out of the way,
let's get rid of this 100% off heading.

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Let's run the git status command, and
we'll see another helpful hint here.

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Use git checkout with the file name to
discard changes in the working directory.

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The git checkout command has
a couple different uses.

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If you don't specify any file names,
git checkout switches between branches.

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We won't be talking about
branches in this course, so

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we won't be covering that usage here.

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If you do specify file names, the contents
of those files will be overwritten

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with their last committed versions.

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Let's try this command out
on the medals.html file.

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We type the git checkout command.

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Then we use some special syntax that is
mainly used together with git checkout,

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a space, a pair of dashes,
and another space.

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This is not a command line option.

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An option would be followed by
an option name rather than a space.

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Instead, it's a separator
that makes it clear to Git

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that any arguments that
follow will be file names.

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Finally, we type the name of one or
more files we want to discard changes for.

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In this case, it will be just medals.html.

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Hit Return to run the command.

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There won't be any output, which as usual,
just means that it was successful.

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Now we can run git diff again.

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Since the changes have been discarded,
it no longer shows any output.

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We can also run get status again, and

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we'll see that the working
directory is clean.

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There are no files that have been
modified since the last commit,

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or rather,

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our medals.html file has been changed
back its state as of the last commit.

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By undoing the modifications to this file,

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we have made another
backwards transition here.

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We've taken a modified file
in our working directory and

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updated its contents to look like
they did in the previous commit.

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We rewound the file from its modified
state back to its last committed state.