Introduction to Unix
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Introduction to Unix Website to load Unix emulator: http://bellard.org/jslinux/ Basic Commands command description pwd present working directory: shows you where you are located in the file system ls list: shows all the files in your present working directory cd change directory: changes the present working directory to another location mkdir make directory: makes a new folder in the specified location cp copy: copy a file to a specified location rm remove: remove the specified file mv move: move file to a new location, or rename a file more more: displays the content of a file cat catenate: reads a file or writes content to a file (end file with CTRLd) echo echo: display the content of a variable emacs emacs: text editor program (use CTRLx, CTRLc to save and exit) wc word count: displays the number of words in a file tar tape archive: extracts a tar file (a type of compressed file) sh shell: executes a shell script grep globally search a regular expression and print: finds text within a file find find: finds a file or directory in the file system top table of processes: shows all running processes (quit with q) kill kill: ends a running process defined by the PID (process ID) cut cut: splits a string into multiple strings defined by a delimiter man manual: displays how to use a command and lists the available options it has command description CTRLc cancel a running process CTRLz suspend a running process CTRLd detach, or end a file when using cat TAB complete filename or command up to the point of uniqueness > write to < read from $ use before variables when referencing them | pipe: allows for the execution of a sequence of commands dash: use this before declaring special options for various commands . signifies current directory; the first character of a hidden file’s name .. signifies parent directory ` execute whatever is in between the `s $RANDOM gives a random number between 0 and 32767 (max int16) Basic Programming for for loops allow for a code to be performed a certain number of times while while loops allow for code to be performed until a specific condition is met do start code to be done in the loops with do done end code to be done in the loops with done if allow for code to run only under certain conditions then if condition is met, do the then elif else if: if the first condition is not met, check new condition else if none of the conditions are met, do the else fi end an if block with fi Tasks 1. Delete the file hello.c in the root folder. 2. Delete the folder dos in the root folder. 3. Write a file named number.list that lists the numbers from 1 to 5 with one number on each line. 4. Create a folder called numbers, and inside of that, create a folder for each number from 1 to 5. 5. Create a new folder called tunnel, and within that another folder called tunnel, and within that another one… repeat until your tunnel is 5 folders deep. 6. Copy number.list to each folder within numbers. 7. Copy numbers to the end of the tunnel. 8. Return to the root directory and find all number.lists within the tunnel. Save the output into number.files. 9. Delete every number.list within the tunnel by making use of number.files. 10. Find all tunnel folders and save the output in tunnel.paths. 11. Write a script, using a for loop, that copies number.list back to all the locations in the tunnel. 12. Repeat all of the above using only scripts, and changing 5 everywhere above to 20. 13. Extra 1: Add a fork in the 20deep tunnel at every 4 tunnel depth, and make each fork 10 deep. 14. Extra 2: Remove all number.lists from the forked tunnel, and add a copy of it to a random location inside the tunnel. 15. Extra 3: Find the randomly placed number.list without using find. .