Join Kevin Skoglund for an in-depth discussion in this video diff: Comparing files, part of Unix for Mac OS X Users.
In this movie we're going to take a look at a Unix tool called DIFF, which is…useful for comparing two files.…Imagine that a client sends you revisions to a text document.…You still have the original document but you can't tell where the client changed.…You could put the two documents side-by- side and then scan each one looking for…the differences then every time you find a difference you could take note of it.…That's exactly what DIFF does for you, but much faster and with greater…precision than you could.…Using DIFF is easy.…Notice that I am inside my user directory and inside unix_files and we're going…to be working with two files that I've added to this directory.…
The first one is original_file.txt, the other one is revised_file.txt.…Both of these are included in the Exercise Files but they're also easy for…you to create yourself.…The first one just has several lines that say delete, several lines that say…change, and several lines that say append.…And then on the far left side I've included the line numbers for reference.…
- Moving around the file system
- Creating and reading files
- Copying, moving, renaming, and deleting files and directories
- Creating hard links and symbolic links
- Understanding user identity, file ownership, and sudo
- Setting file permissions with alpha and octal notation
- Changing the PATH variable
- Using the command history
- Directing input and output
- Configuring the Unix working environment
- Searching and replacing using grep and regular expressions
- Manipulating text with tr, sed, and cut
- Integrating with the Finder, Spotlight, and AppleScript
Skill Level Beginner
Q: The exercise files for the following movies appear to be broken:
Is there something wrong with them?
These exercises include one or more "dot files", whose file names start with a period. These files are normally hidden from view by the Finder. So that they would show up in the Finder, the period has been removed from the file names. Additionally, "_example" has been added at the end of the file name to make it clear that the file will not work as-is.
To make the dot files usable, either:
1) Open the file in a text editor to view its contents. Note that it may not be possible to double-click the file to open it because there is no file extension (such as .txt).
2) Resave the file under a new name (usually by choosing File > Save As), adding a "." to the beginning of the file name and removing "_example" from the end.
1) Copy and rename the file from the Unix command line using the techniques discussed in this course. Rename the file by adding a "." to the start and removing "_example" from the end. Include the "-i" option to prevent overwriting an existing file unexpectedly.
Example: cp -i ~/Desktop/Exercise\ Files/Chapter_07/07_02_files/bashrc_example ~/.bashrc
The instructor uses the UNIX program 'units' to convert 72° Fahrenheit to degrees Celsius. The returned value of 40 is incorrect. The correct result should be 22°C. What's the reason for this discrepancy?
The problem is that units does the 5/9 calculation but does not have the ability to subtract 32. So you'll need to subtract (or add) the 32 degrees yourself.
1. Introduction to Unix
2. Filesystem Basics
3. Working with Files and Directories
4. Ownership and Permissions
5. Commands and Programs
6. Directing Input and Output
7. Configuring Your Working Environment
8. Unix Power Tools
9. Useful Mac-Only Commands and Techniques
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