3.18.2 Greatest hits from previous weeks

Greatest hits from previous weeks:

3.18.2.1 What commands are there for horizontal spacing?

https://tex.stackexchange.com/questions/74353/what-commands-are-there-for-horizontal-spacing

I know that \: in LaTeX produces a space when rendered. 
Are there any alternatives, because my LaTeX renderer doesn't support \: (it renders it as text), and there is no help / FAQ that I can find.
 

- asked by think123 (396 votes), answered by Werner (551 votes)

3.18.2.2 Mavericks upgrade screwed up my pdflatex (command not found)

https://tex.stackexchange.com/questions/163849/mavericks-upgrade-screwed-up-my-pdflatex-command-not-found

so everything was working fine ... until i upgraded to os x mavericks (version 10.9.2) a couple days ago. 
using 
emacs version 24.3 (9.0) 
auctex version 11.87.3 
after upgrade, tried to compile and  ...
 

- asked by MichaelWBratton (33 votes), answered by Sean Allred (30 votes)