Shows all hidden files and folders along with normal ones.

ls -a

list lot of information about non-hidden files and directories

la -l

list above info for hidden files and directories too

ls -la OR ls -l -a

to switch to a dir same as cd but it just saves the path from which you came

pushd <path>

to switch back to dir from which you came with pushd.

popd

tells details of file

file <name of file>

search a directory or a file in data base

locate <name of file or directory>

or

mlocate <name of file or directory>

NOTE: run before locate/mlocate to update database

sudo updatedb

see calander

cal