Glob pattern

? - Single character wildcard

ls badge?.txt
ls ?????.txt

* - Character sequence wildcard

ls source.*
ls badge*

[] - Character set wildcard

ls badge_0[246].txt
ls badge_[01][789].txt
ls badge_[23][1-5].txt

& - Background process (launch an application as a
background process and continue to use the
terminal window)

gedit command_address.page &

< - Input redirection sort < words.txt
> - Output redirection ls > files.txt
$ - Variable expressions echo $PATH