Emacs Flaw: fill-paragraph fill-region
What is Emacs Fill Commands
Emacs has a command fill-paragraph 【Alt+q】.
It reformats the current paragraph into multiple lines, by inserting a newline char at every ~70 chars.
Emacs also has fill-region, which acts on a text selection.
However, there are some usability problems with these commands. This page discuss the problems and fixes.
Problems of Emacs Fill Commands
It is inconvenient to “unfill” a paragraph or region.
One frequently asked question is how to “unfill” — do inverse of fill-paragraph.
Technically, this means replacing newline char by space.
Emacs does not have a built-in command for this.
The typical solution is to set the cut-width to a huge number (e.g. set fill-column to 10001000), then Alt+x fill-paragraph, then set fill-column back to previous value.
If you need to reformat several paragraphs, use Alt+x fill-region.
There is no keyboard shortcut.