Referencing the child of a commit in Git

Question

If you want to move the HEAD to the parent of the current HEAD, that's easy:

git reset --hard HEAD^

But is there any simple way to do the exact opposite of this operation, that is, set the head to the current head's first child commit?

Right now, I use gitk as a workaround (alt-tab, up-arrow, alt-tab, middle-click), but I would like a more elegant solution, one that can also be used when gitk is not available.

question from:https://stackoverflow.com/questions/1761825/referencing-the-child-of-a-commit-in-git

Answer 1

Very probably not the fastest possible solution, but it does what I need:

#!/bin/bash

REV=$1

if [[ -z "$REV" ]]; then
    echo "Usage: git-get-child  []"
    exit
fi

HASH=$(git rev-parse $REV)

NUM=$2

if [[ -z "$NUM" ]]; then
    NUM=1
fi

git rev-list --all --parents | grep " $HASH" | sed -n "${NUM}s/([^ ]*) .*$/\1/p"

The git rev-list --all --parents does exactly what I need: it iterates over all reachable commits, and prints the following line for each:

SHA1_commit SHA1_parent1 SHA1_parent2 etc.

The space in the grep expression ensures that only those lines are found where the SHA1 in question is a parent. Then we get the nth line for the nth child and get the child's SHA1.