Can you explain what is meant by the 'squash' command in the Git version control system?

In Git, the 'squash' command is used to combine multiple commits into one. This helps make the change history cleaner and more understandable, especially before merging branches.

For example, when performing a rebase with the squash option, you can combine several small commits into a more significant one:

git rebase -i HEAD~3

In interactive mode, instead of pick, some commits are selected as squash, which merges them with the previous commit.

This is convenient for removing unnecessary intermediate commits and keeping only important changes in the history.