Useful Linux Commands

To find help page of command
      apropos grep
View files in directory
      ls -lt
To view all files including hidden files
      ls-lat
To search folder or file
      ls-lat|grep Desk*
 To know present directory
      pwd
To know  location of proces
      pwdx

To Search in zip file
       zipgrep -x

To check memory
      ram
      free
      top
      vmstat
      prstat