Unix Command - ls

When ls invoked without any arguments, lists the files in the current working directory. A directory that is not the current working directory can be specified and ls will list the files there. The user also may specify any list of files and directories. In this case, all files and all contents of specified directories will be listed.

Files whose names start with "." are not listed, unless the -a flag is specified or the files are specified explicitly.

Without options, ls displays files in a bare format. This bare format however makes it difficult to establish the type, permissions, and size of the files. The most common options to reveal this information or change the list of files are:

-l    long format, displaying Unix file type, permissions, number of hard links, owner,     group, size, date, and filename

-F    appends a character revealing the nature of a file, for example, * for an executable, or / for a directory. Regular files have no suffix.

-a  lists all files in the given directory, including those whose names start with "." By default, these files are excluded from the list.

-R  recursively lists subdirectories. The command ls -R / would therefore list all files. 

$ ls
$ ls -a
$ ls -laF ~/public