Linux vi and Scala 8 29 2011 Opening Discussion What did we talk about last class Reason for PoP II question Minute Essays Does command line interact with the internet Files and Directories What you call folders were originally directories Commands pwd See current directory ls List the contents of a directory mkdir rmdir Make and remove directories cp mv rm Copy move remove files less more cat See contents of files Tips Tab completion for file directory names for last matching command Ctrl r to search your history The man command for manual entries Use the k option to search Permissions Do ls with l option to see permissions Sets of rwx for user group and others Use whoami and groups to find identity Use chmod and chown to change permissions or ownership Remote Use ssh to login into one machine from another Use scp to copy files from one machine to another The website has a link to Putty which will give you these abilities from Windows Other du Lists disk usage grep Searches for something inside of files find Find files head List the first several lines of a file tail List the last several lines of a file top Look at what is running on a machine w Look at who is logged into a machine I O Redirection You can send a programs output to a file using or You can make a program use a file as input using You can do more interesting things by sending the output of one program to another with Text Files Editors Programs are typically written as plain text files and should be edited with a text editor Notepad is a basic text editor on Windows Word is NOT a text editor Some text editors are better than others for programming In this class we will use vi vi The vi editor is standard on Linux which is one reason we like to use it It is also good for programming Has modes Start in command mode You type in an edit mode i insert I insert at beginning of line a append A append at end of line R replace characters Other Commands x delete characters dd delete cut lines yy yank copy lines p or P paste before or after r replace a single character J join lines and n search for something and next cw change a word repeat last command u and Crtl r Undo and redo Scala Script First Program Let s make a directory and use vi to write our first Scala program then run it The standard first program is Hello World and I don t want to break with tradition Minute Essay Next class we really move into Scala Any questions about command line and vi If you didn t answer this on Friday let me know if you are considering taking PoP II in the Spring We are already in the process of building schedules The book contains a LOT more information than we can get through in class Read and practice
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