Finding doubled words
The standard spelling tools of Emacs and other editors commonly miss the occurence of doubled words such as "the the" in a sentence. An excellent and fast solution is to use egrep. I found the following solution in the book Mastering Regular Expressions. Here is the command that searches all .tex files in my folder of a Latex project and filters the lines with doubled words
egrep -i '\<([a-z]+) +\1\>' *.tex
Jan. 16, 2021, 3:23 a.m. by tkhvxtlgdl