Modern OSS projects have adopted Git to manage versions of their source code and GitHub for hosting their Git repositories. GitHub provides a characteristic feature notably pull request, and many projects adopt pull-based development model by using it. This development model offers an opportunity to review the source code before merging it into the mainstream. Getting acceptance of the pull request, any developer should strictly follow the flow of pull-based development. To follow the flow, she/he needs to use correctly Git commands. However, using these commands is complicated and requires further knowledge of them. In this paper, we conducted a large-scale survey of 1552 developers on GitHub to investigate the difficulty of the Git from the aspect of the pull request. The result shows developers struggle with 'git rebase -i' command tends not to perform re-ordering, compressing and dividing their commits.