Fixed a typo where 'ls' was 'cat' (#30629)

* Fixed a typo where 'ls' was 'cat'

'ls' was written as 'cat' in the usage pane. Also made some grammatical changes and changed the location of the directory usage example.

* Update index.md

guide/english/bash/bash-ls/index.md

@@ -4,7 +4,7 @@ title: Bash ls
 
 ## Bash ls
 
-`ls` is a command on Unix-like operating systems to list contents of a directory, for example folder and file names.
+`ls` is a command on Unix-like operating systems to list contents of a directory such as folders and file names.
 
 
 ### Usage