EECS 183 Discussion 2 Milind Furia

EECS 183 Discussion 2 Milind Furia Adapted from: Anna Wasewicz Using a VM • a virtual machine (VM) is a fake computer running as a program. • It can be used as a playground to test things out and work without risking anything on your day-to-day machine. • It can also be used for development if you don’t have a Unix based system (ex. Windows) VM Caen Linux • http://caenfaq.engin.umich.edu/12374-Linux- Login-Service/how-do-i-connect-to-a-caen- linux-computer-remotely The command line • a tool into which you can type text commands to perform specific tasks Instead of using the gui with your mouse to click on things to accomplish tasks • A lot of things can be automated using the command line Some simple commands • ls (list space) • -l to the end of my ls command, I'll see a detailed listing • -t will sort the results by file time • -S will sort by file size • -r will reverse the sorting • –a lets you see hidden files there are two entries for "." and ".." at the beginning of the list. "." is the current folder. “..” is the parent folder cd (change directory) • Lets you navigate which folder you are in • You can navigate to either full or relative paths. • If you're in /path/to/ and you want to navigate to the folder stuff inside that folder, you can simply type: cd stuff pwd (list working directory) • tells you which directory you are in Creating and removing folders • To create a new folder, use the mkdir <foldername> command • Remove any folder with the rmdir <foldername> • If the folder is not empty, this command will not let you delete the folder. If you want to remove the folder and all it’s contents you can use rm –rf <foldername> be careful with this! the –f flag stands for force the –r flag stands for recursive Creating and removing files • use the touch <filename> command to create a new, blank file • use the rm <filename> command to delete files Kleene Star ( * ) • means match everything • if you're in a folder and want to delete every file inside that folder, just type: rm * • Delete every instance of a matching filename pattern from the current directory and below: rm –rf filename.* Edit files using command line • The command that you use to edit text files will be different based on the platform you're using • Linux has the nano editor to quickly edit files, which might be more suitable for beginners. • nano /path/to/file • I recommend vim or vi or gvim grep command • utility for searching plain-text data sets for lines matching a regular expression • used to quickly find text within files, even searching through subdirectories. • if you wanted to search through all files in the current directory and below it for "text string", you could use this command: grep –ir "text string" * Shortcuts • Ctrl + U: Clears the line from the cursor point back to the beginning. • Ctrl + A: Moves the cursor to the beginning of the line. • Ctrl + E: Moves the cursor to the end of the line. • Ctrl + R: Allows you to search through the previous commands. Quiz Questions!! On the spot Regex • What the * is this? [0-9]{3}[-. \)$]*[0-9]{3}[-. \\$\(]*[0-9]{4} Regexes • is a sequence of characters that define a search pattern, mainly for use in pattern matching with strings • can be used for find and replace tasks • grep is what you can use on the command line to match regular expressions A Regular Expression contains one or more of the following: • A character set: characters retaining their literal meaning • An anchor: These designate (anchor) the position in the line of text that the RE is to match. For example, ^, and $ are anchors. • Modifiers: These expand or narrow (modify) the range of text the RE is to match. Modifiers include the asterisk, brackets, and the backslash..

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