Linux Commands: 

1. Pwd  =  Present Working directory.

Its referred for abosulate path in your current working directory. even if analyzed for in which user are current working directory.

2. ls Command:

ls command is displaying the contents of the current working directory and specific working directory.

ls -a:

This command is used and displaying the hidden files and directory.whose its begin with (dot) = .

For example like as, 

.bash_profile , bash_account, .public_html

ls -l:

This command is displaying the extra information .because its displaying the long  listing contents with more information.

ls -d:

Its displaying for only directories . even not to their contents also.

ls -ld:

This command is displaying the directories and symlink information.

ls -R:

Re-curse through the sub_directories