ls - technical definition

(LiSt) The command in Unix/Linux, including Mac OS X, that displays file names in the directory (folder). It is the counterpart to the DIR command in Windows and DOS. Following are some brief examples. Note that commands are case sensitive; for example, file names with upper case extensions must be expressed with upper case characters in the command; the same for lower case.

   ls      list all files
   ls -l   list all files with details

   ls *.GIF      list GIF files
   ls *.gif      list gif files
   ls *.gif -l   list gif files with details

   ls | wc -l         count all files
   ls *.GIF | wc -l   count GIF files
   ls *.gif | ws -l   count gif files
   (wc = word count)