Selecting text while jumping with cursor in iTerm2
You can setup key shortcuts for this functionality in iTerm2.
In Prefs > Profiles > Keys you can assign keys to move the beginning or end of the selection by a single character, word, or line. No such keys are bound by default.
To make a shortcut for the precise text selection you are referring to you would assign the shortcuts to the following actions,
⇧ ⌥ → = Move end of selection forward, Move by word
⇧ ⌘ → = Move end of selection forward, Move by line
Source: https://www.iterm2.com/documentation-one-page.html