shit-happens chapter :P

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blinry 2021-01-05 16:58:42 +01:00
parent 9109394271
commit 12ea306302
7 changed files with 169 additions and 0 deletions

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stash stash
index index
shit-happens
time-machine time-machine
low-level low-level

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title = Undo a bad commit
cards = reset commit-a
[description]
Oh no, we made a bad commit! How can we undo making the commit, and go back to a point where we can try again?
The answer is using `git reset [commit]`, which does two things:
- It resets the current branch ref to the commit you specify.
- And it resets the index to that commit.
It does not change your working directory in any way, which means that after that, you can try making the commit you want again.
[setup]
echo "1 2 3 4" > numbers
git add .
git commit -m "Initial commit"
echo "1 2 3 4 5 6 7 8 9 11" > numbers
git commit -am "More numberrrrrs"
[win]
# In the last main commit, the numbers file contains the numbers from 1 to 10.
test "$(git show main:numbers)" = "1 2 3 4 5 6 7 8 9 10"
# The commit message of that commit is "More numbers".
git log -1 --oneline | grep "More numbers"
# The commit with the typo is not part of the main branch anymore.
git log --oneline | grep -v "rrrrr"

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title = I pushed something broken
cards = revert push
[description]
We were talking about how to undo a commit, and fix it. This only helps when you haven't already pushed it to a remote. When that has happened, and you want to undo the effects of the commit completely, your best option is `git revert`
[setup]
echo "this is fine
?
?
?" > text
git add .
git commit -m fine
echo "this is fine
this is also fine
?
?" > text
git commit -am "also fine"
echo "this is fine
this is also fine
this is very bad
?" > text
git commit -am "very bad"
echo "this is fine
this is also fine
this is very bad
this is fine again" > text
git commit -am "fine again"
git push team main
git branch -u team/main main
[setup team]
[win team]
# The team's main branch no longer contains the bad thing.
! { git show main:text | grep -q "very bad"; }
# And the history has not been modified.
git show main^:text | grep -q "very bad"

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title = Go back to where you were before
cards = checkout reflog
[description]
Say you were looking at something in the past, and then switched back to the main branch.
But then, you got reaaally distracted, and after your lunch break, you can't remember on which commit in the past you were before. How can you find out?
There's a convenient command that shows you all the places your HEAD did point to in the past:
git reflog
[setup]
for i in {1..10}; do
git commit --allow-empty -m $i
git branch $i
done
git checkout 3
git checkout main
[win]
# Find out where you've been before, and go back there!
test "$(git rev-parse HEAD)" = "$(git rev-parse 3)"

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title = Restore a file from the past
cards = checkout checkout-from commit
[description]
Here's a similar problem: you really liked the essay from the very first commit, and want to have it back! Well, checkout can also restore things from older commits, Here's how:
git checkout [commit] [file]
[setup]
echo "good version" > essay
git add .
git commit -m "Initial commit"
echo "bad version" > essay
git commit -am "\"Improve\" essay"
[win]
# Get the first version of your essay, and make a new commit with it.
test "$(git show main:essay)" = "good version"

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title = Restore a deleted file
cards = checkout
[description]
Oops - you deleted the "essay" file, which you worked on all night!
Luckily, Git is here to help! You can use `git checkout` to restore the file!
[setup]
echo important > essay
git add .
git commit -m "Initial commit"
echo "important content" > essay
git commit -am "Improve essay"
rm essay
[win]
# Make changes to all three files, and add all of them to the index.
test "$(cat essay)" = "important content"

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"command": "git checkout [commit, ref, file]", "command": "git checkout [commit, ref, file]",
"description": "Drag this card to a commit or to a branch to travel to it!\n\nAlternatively, reset changes in a local file." "description": "Drag this card to a commit or to a branch to travel to it!\n\nAlternatively, reset changes in a local file."
}, },
{
"id": "checkout-from",
"command": "git checkout [commit, ref] [file]",
"description": "Get the file contents from the specified commits, and reset both the working directory, as well as the index, to it."
},
{ {
"id": "commit-a", "id": "commit-a",
"command": "git commit -a", "command": "git commit -a",
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"command": "git cherry-pick [commit]", "command": "git cherry-pick [commit]",
"description": "Repeat the specified action on top of your current timeline." "description": "Repeat the specified action on top of your current timeline."
}, },
{
"id": "revert",
"command": "git revert [commit]",
"description": "Make a new commit that reverts the changes of the speicified commit."
},
{ {
"id": "bisect-start", "id": "bisect-start",
"command": "git bisect start", "command": "git bisect start",
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"command": "git branch -D [ref]", "command": "git branch -D [ref]",
"description": "Delete a branch." "description": "Delete a branch."
}, },
{
"id": "reflog",
"command": "git reflog [ref, head]",
"description": "Display a log of there the ref pointed to in the past."
},
{ {
"id": "file-new", "id": "file-new",
"command": "touch [string]", "command": "touch [string]",