Knowledge of the Command Line is essential!
- Necessary to compile programs from source (much easier than loading into IntelliJ or other IDE)
- Necessary when working with remote machines (i.e., servers and clouds)
- Compact, unambiguous, way to represent instructions for doing things
- Allows complex tasks to be automated (almost anything can be scripted)
- Basically, it is a powerful tool for scaling your activities to many things!
- The Unix Philosophy as summarized by Doug McIlroy
- Write programs that do one thing and do it well
- Write programs to work together
- Write programs to handle text streams, because that is a universal interface
- Basically, everything works via abstractions!
- For example: everything is treated as a "file": files, network data, the keyboard and mouse, even the output of commands
- From the Ubuntu web site:
"As any Linux user knows, it's the command line terminal where the magic happens. It's perfect for file management, development, remote administration and a thousand other tasks."
Useful Commands
ls list contents of a directory cd change the working directory cp copy files mv move files rm remove files (be careful — no UNDO!) mkdir make a directory grep look for strings in a file matching a given criteria diff report differences between files find find files matching a given criteria sort sort data based on variety of criteria tar compress/uncompress files man help page for a command Using arguments and wildcards can make these commands target specific types of data
cat output the contents of a file less page through a file head show the first lines in a file tail show the last lines in a file nano simple in shell text editor vi complex in shell text editor emacs complex in shell text editor
- Use a Virtual Machine (VM): VirtualBox (free), VMware (Duke has a site license)
- Boot from CD or USB drive (knoppix)
- Dual boot your machine
- Directly on your machine (can be dangerous): Linux, Mac, Cygwin on Windows, Ubuntu on Windows (now with Copy/Paste)!
Working with the Filesystem
- File permissions
- File types
- What is sudo?
Never type "rm -r *" or especially "sudo rm -r /*"