How easier than `git rebase -i`? Running this command, opens your editor of choice with this text & an extensive help commented out at the bottom:

    pick 5340360 # First commit.
    pick 12ccd8a # Second commit.
    pick a2b6a59 # Fourth commit.
    pick 2a648f2 # Commit #4.
    pick 6bb5d98 # Commit #5.
    pick af1f2fe # Commit #6.
    pick 7e99e85 # Commit #7.
    pick 7567b18 # Commit #8.
    pick c23819d # Commit #9.
    pick 50941da # Commit #10.

You edit it to (due to help don't really have to remember a single command):

    pick 5340360 # First commit.
    pick a2b6a59 # Fourth commit.
    pick 2a648f2 # Commit #4.
    reword 12ccd8a # Second commit.
    edit 6bb5d98 # Commit #5.
    squash 7e99e85 # Commit #7.
    pick af1f2fe # Commit #6.
    squash 7567b18 # Commit #8.
    drop c23819d # Commit #9.
    pick 50941da # Commit #10.

And then after letting you reword 12ccd8a, edit 6bb5d98, write new messages for (post-edit) 6bb5d98&7e99e85, and af1f2fe&7567b18, you get:

    pick 5340360 # First commit.
    pick 2448f03 # Fourth commit.
    pick 9cefee3 # Commit #4.
    pick 1259a52 # Second "Hi" commit.
    pick 2ca48d8 # Commit #5.Commit #7.
    pick 4bf7bcd # Commit #6.Commit #8.
    pick dbbb733 # Commit #10.

And if you messed up anything, you can always undo it by using your `git reflog`. No matter what you did, you can always go back a previous state! Each state is stored as new commit.

    dbbb733 (HEAD -> master) HEAD@{18}: rebase (finish): returning to refs/heads/master
    dbbb733 (HEAD -> master) HEAD@{19}: rebase (pick): Commit #10.
    4bf7bcd HEAD@{20}: rebase (squash): Commit #6.Commit #8.
    cdc47c1 HEAD@{21}: rebase (pick): Commit #6.
    2ca48d8 HEAD@{22}: rebase (squash): Commit #5.Commit #7.
    6a6fccc HEAD@{23}: commit (amend): Commit #5.
    86ca5f8 HEAD@{24}: rebase (edit): Commit #5.
    1259a52 HEAD@{25}: rebase (reword): Second "Hi" commit.
    b33f89c HEAD@{26}: rebase (reword): Second commit.
    9cefee3 HEAD@{27}: rebase (pick): Commit #4.
    2448f03 HEAD@{28}: rebase (pick): Fourth commit.
    5340360 HEAD@{29}: rebase: fast-forward
    d1406ed HEAD@{30}: rebase (start): checkout d1406ed8145dc84695eb622bc6b3fc078e8098df
    50941da HEAD@{31}: commit: Commit #10.
    c23819d HEAD@{32}: commit: Commit #9.
    7567b18 HEAD@{33}: commit: Commit #8.
    7e99e85 HEAD@{34}: commit: Commit #7.
    af1f2fe HEAD@{35}: commit: Commit #6.
    6bb5d98 HEAD@{36}: commit: Commit #5.
    2a648f2 HEAD@{37}: commit: Commit #4.
    a2b6a59 HEAD@{38}: commit: Fourth commit.
    12ccd8a HEAD@{39}: commit: Second commit.
    5340360 HEAD@{40}: commit (initial): First commit.

Feel like git has a reputation for being hard even for things they're not that much.